Book data service system with data delivery by broadcasting

ABSTRACT

A book data service system in which the book data can be delivered by the broadcasting such that the book data can be delivered to any user located at any place promptly and economically, without causing the waste of the resources. A book data service system if formed by at least one data center including: a data center computer for storing and managing book data; and a broadcasting facility for broadcasting the book data stored and managed by the data center computer according to a prescribed communication protocol using a synchronization control and an error correction scheme suitable for data delivery by broadcasting without confirmation from a receiving side; and a plurality of user terminals, each user terminal including: a receiver for receiving the book data broadcasted from the broadcasting facility of the data center; a user terminal computer for storing and managing the book data received by the receiver; and a display for displaying the book data stored and managed by the user terminal computer.

BACKGROUND OF THE INVENTION

[0001] 1. Field of the Invention

[0002] The present invention relates to a system for presenting data inan image of a book, and more particularly, to a book data service systemin which the book data can be delivered by the broadcasting, only thenecessary book data can be selectively stored, the service can becharged according to the accesses to the book data actually made, andthe feedback from the user to a data center can be supported.

[0003] 2. Description of the Background Art

[0004] In conjunction with the wide spread of the computers, variousschemes for making it easier for a user to utilize the computer havebeen developed, including the so called Book-Metaphor which is anexample of a system generally called electronic book in which the dataare presented in an image of a book. The Book-Metaphor is a scheme fordisplaying the data on a computer in an image imitating a visualappearance of a usual book, in which various operation functionsassociated with the usual book such as a jumping from the table ofcontents to a desired page, turning pages one by one, etc. are alsosupported. The software for this Book-Metaphor comprises book dataproduced in accordance with the prescribed format, and a program for thedisplay of the book data along with the operation functions of a book.

[0005] An exemplary book data display image in the Book-Metaphor isshown in FIG. 1, which incorporates a number of navigation buttons forselectively activating the operation functions of a book supported inthe Book-Metaphor arranged below the image of the book. Here, assummarized in FIG. 2, the navigation buttons include (a) a button forcommanding a display of the front cover, (b) a button for commanding adisplay of the back cover, (c) a button for commanding a display of anext page (one page forward shift), (d) a button for commanding thedisplay of a previous page (one page backward shift), (e) a button forcommanding a continuously forward shift, (f) a button for commanding acontinuously backward shift, (g) a button for commanding anattaching/removing of a slip, (h) a button for commanding a restoring ofan original state before the previous operation (undo), and (i) a buttonfor commanding an end of the use of the Book-Metaphor. it is noted thatthe types and shapes of the navigation buttons are not necessarilylimited to those shown in FIGS. 1 and 2 and described here, but thebuttons for shifting one page forward and backward are indispensable. Inaddition, the Book-Metaphor also incorporates a basic function fordisplaying a page having a table of contents on which any desiredchapter or section can be specified, and displaying a page correspondingto the desired chapter or section specified.

[0006] In the exemplary display shown in FIG. 1, the image of the bookincorporates a number of tags attached on a side edge of the book, whichare shifted when the pages are shifted, and a number of slips attachedon an upper edge of the book which can be attached or removed by thenavigation button (g) mentioned above. When any of these tags or slipsis specified, the page at which the specified tag or slip is attached isopened immediately.

[0007] Using this Book-Metaphor as described, it becomes possible for auser to read a series of data quickly in a manner similar to that ofreading a usual book, in addition to the ordinary manners of utilizingthe computer such as the processing of the entered data, the retrievalof a desired data from the database, etc. In particular, as the size andweight of the computer are progressively reduced, it is feasible forthis Book-Metaphor to replace the conventional books in future. Inaddition, in this Book-Metaphor, the manner of data access is sointuitive that practically anyone can understand it immediately, so thatit is particularly suitable for a case requiring a continuous access toa series of very large data, in contrast to the conventional data accessscheme in which it is necessary to narrow down the range of data to bedisplayed minutely by interactive operations, which is not necessarilyintuitive for anyone.

[0008] Conventionally, the available means for entering the book data insuch a Book-Metaphor system included the exchangeable memory medium suchas floppy disks, CD-ROMs, and IC memory cards. Namely, the data providermust outputs the produced book data to the exchangeable medium once andthen offers the exchangeable medium to the user, while the user must usethe book data by displaying the stored book data using a book datadisplay program, either directly from the exchangeable medium or bycopying them to a large capacity file memory.

[0009] In such a conventional scheme using the exchangeable medium forentering the book data into the system, the medium storing the book datamust be sold just as the books or video tapes are sold today. However,except for a case of buying the widely distributed materials such asmagazines, the user still have to suffer from the tedious inconvenienceof finding an appropriate bookstore first, and then finding a desiredbook in the bookstore. Also, the data provider may also suffer from theproblems of the excessive returned copies or the shortage of the stockcopies unless the sales of the book is properly judged beforehand.Moreover, as a physical medium for carrying the data is required foreach copy, there is also a problem concerning the waste of resources.

[0010] As for the management of the electronic books, as the mediumstoring the data of the electronic book has conventionally been sold atthe bookstore in a manner similar to the usual book, a large number ofsuch media must be managed by the user in a manner similar to the usualbooks. In addition, even when the user terminal is equipped with a largecapacity files capable of storing a plurality of electronic books, ithas been difficult to manage a number of independently acquired bookdata efficiently. Thus, in the conventional electronic books, only themanner of data access and display on the computer have been changed,without changing the manner of providing data and managing data.

[0011] Also, when the book data of the electronic book contain thequestionnaire or the advertisement for the mail-order, the feedback fromthe user has been relying on the mail or the telephone just as in a caseof the usual books.

[0012] As such, compared with the conventional book in paper, theelectronic book has advantages related to the possibility of multi-mediaexpression, the powerful data retrieval operation, and the data storagerequiring less storage area, but it is still unable to come even closeto the conventional book in terms of the beauty of the visual appearanceand the easiness of the visual comprehension. Consequently, in order toexpect the full-scale spread of the electronic books, it appearsnecessary to take more advantages of their electronic nature in theaspects related to the manners of providing data, managing data, andsupporting the user feedback.

[0013] On the other hand, there has been a system in which the databasecan be remotely inspected from a data center interactively, or a systemwhich broadcasts the mainly text data repeatedly in short cycles, suchthat the user at the user terminal can selectively acquire and displaythe broadcasted data as if the user has interactively communicated withthe data center. However, it has been impossible to make accesses to avariety of data freely in such a conventional system because of thesevere conditions required for the communication cost and the amount ofdata that can be delivered within one cycle of the broadcast. Inparticular, it has been impossible in such a conventional data accessscheme to make a continuous access to the very lengthy data withoutminutely specifying the range of the desired data, as required indealing with the contents of the books.

[0014] As for the method of access to the data stored in the database,the conventionally available methods included a method using the commandor the keyword entered by the user, and a method for selecting from amenu. However, in the method using the user's command input, there is aneed for the user to remember the special command, whereas in the methodusing the user's keyword input, there is a problem that the user mustenter the keyword as registered in the database itself. On the otherhand, in the method for selecting from a menu, especially when thedatabase is of a very large scale, the database has a complicated datastructure which requires many hierarchical levels in menu such that theselection of a desired data becomes difficult especially when theclassification made used in the database differs from the classificationmade by the user. Moreover, in this method for selecting from a menu,the operation of the system is difficult such that a considerable amountof time is required in acquiring sufficient system operation skills.

[0015] As a solution for these problems, the aforementionedBook-Metaphor is also effective, because in the Book-Metaphor, inaddition to the data retrieval based on the index or the list display,it is also possible to realize the data retrieval by browsing throughthe data content of the database in a manner of turning pages one byone, so that it becomes easier to comprehend the data structure and theoperation method from the viewpoint of the data retrieval. In otherwords, it becomes possible to make a necessary access to the data evenwithout knowing the specific keyword for each data.

[0016] Now, in conjunction with the development of the communicationtechnology, the utilization of the database data through thecommunication network has become fairly common, and it is expected thatthe utilization of the database data is going to play even moreimportant role in our society in future. As the data plays increasinglymore important role, there arises a problem concerning the security ofthe data. Also, there is a need for a system which provides the dataonly to the selected users having specific rights assigned, in which theusers making access to the data must be charged for the use of thedatabase data. Conventionally, the charging for the utilization of thedatabase data has been realized by carrying out the charging processingon the host computer side at a time of transmitting the data content ofthe requested data from the database.

[0017] Moreover, as a method for protecting the security of the data,several digital enciphering methods have been developed, and aconventional scheme for protecting the security of the data has been theuniform enciphering of all the data to be transmitted to the user sideaccording a certain enciphering algorithm. However, in such aconventional scheme, because no clue for recognizing the data contentshas been provided, in a case of the retrieval and display of the bookdata, there arises the problem that the selection of the necessary datacannot be made. For this reason, there has been a proposition of ascheme for deciphering only a part of the data content so as to providea clue for the retrieval of the data contents.

[0018] However, when the deciphering of the enciphered data at the userterminal side is allowed freely, there arises the problem that theaccurate charging processing for the utilization of the data becomesimpossible. Moreover, when the enciphered data are transmitted for thepurpose of the data retrieval, the data content to be accessed must beenciphered and transmitted once again at the host computer side afterthe selection of the desired data was made, so that the security of thedata cannot be maintained and the amount of communication can also beincreased as it is necessary to transmit the same data content twice.

[0019] Also, in a case of measuring the utilization state of the datadelivered by the broadcasting, the conventionally employed method hasbeen that in which a recording device given to a specific data user inadvance is connected to a receiver device and the utilization state ofthis specific user is recorded. However, the data user can utilize thebroadcasting even when the recording device is disconnected from thereceiver device so that there is a possibility for the specific datauser to disconnect the recording device, and therefore it has beenimpossible to make the accurate measurement of the utilization states ofall the data users.

[0020] Also, in a case of utilizing the enciphered data delivered by thebroadcasting, as the data cannot be utilized unless the data aredeciphered, it has been necessary for the data user to connect a decoderfor deciphering the enciphered data to the receiver device. However,conventionally, the decoder without the measurement function has beenused for this purpose, so that at a time of charging the fee forutilization of the data to the data user, a particular data utilizationfee independent of the amount of data utilization has been charged. Froma point of view of the user, this implies that the same fee is chargedeven when the amount of data utilization is small so that the user mayvery well consider it as unfair, and this has been a reason for maypotential users to refrain from subscribing to the use of the datadelivered by the broadcasting.

[0021] On the other hand, conventionally, there has been a discussion ofa data communication system for carrying out exchanges of the book dataamong a plurality of systems connected through a network, so as to makeit possible for a variety of people to obtain various book data easily.In addition, there has also been a discussion of a manner of displayingthe obtained book data to be as easily readable as possible.

[0022] However, as a huge number of data become obtainable by such adata communication system, it rather becomes difficult for each user tosmoothly select and store the data which are actually required accordingto each user's need.

[0023] Now, the usual book in paper often contains a questionnaire, aquiz, or a solicitation for the reader's opinions or impressions, whichrequires the feedback from the user, and in such a case, the feedbackfrom the reader to the publisher is normally made via mail or facsimile.

[0024] However, in a case of making the feedback to the publisher viamail or facsimile, the reader is required to carry out a work of mailingor facsimile transmitting, which has a qualitatively quite differentnature from that of the work of reading, so that it can interrupt theflow of the reading work. Also, because of the reluctance to take atrouble of carrying out the work of qualitatively quite different natureon the user side, the sufficient amount of feedbacks cannot be collectedfrom the users in many cases. From the point of view of the publisher,in a case of computer processing the information obtained from the userfeedback, it requires a considerable time and labor to read the contentsof the mail or facsimile and entering necessary information into acomputer, and it in turn requires a considerable cost and time for thishuman labor.

[0025] On the other hand, there is a book in a form of a catalogueaccording to which the user can make an order for items or a reservationfor an event. From the point of view of the publisher of this catalogue,there is a work of receiving the orders from the readers, and for theautomation of such a work, there has been an order receiving system or areservation accepting system in which the order data or the reservationdata produced by an order slip production tool provided on a personalcomputer can be transmitted via a personal computer communicationnetwork to a center for receiving orders. Also, in the so calledvideotex, there is provided an order entry system in which the orderdata, reservation data, or answer data for questionnaire can be enteredin a manner of interactive dialogue with the center.

[0026]FIG. 3A shows an example of an order receiving system using apersonal computer, which comprises a host computer 1 equipped with ahost terminal 2 located at a data center, which is connected with a userterminal provided by a personal computer 3 through a communicationnetwork 4. Here, the communication network 4 can be a transparentnetwork such as the telephone network or ISDN, or a value added network.In a case of the value added network, it can either be a network inwhich the end-to-end dialogue is supported by the protocol conversionthat can be carried out in real time at the network, or a network inwhich the data transmission and reception can be executed for the usersby the network which has long time storage function.

[0027]FIG. 3B shows an operation sequence in a case of using either atransparent network or a value added network supporting the dialoguetype communication. From the point of view of the dialogue between theterminals, there is no difference among these networks. In the operationsequence of FIG. 3B, in a case the user makes an order, the orderingsoftware is activated at the user terminal personal computer 3, and theorder slip is produced by the dialogue between the user and the personalcomputer 3. Then, the communication software is activated from theordering software, and the communication path is set up with respect tothe host computer 1 through the communication network 4. Here, the hostcomputer 1 is in a state of waiting for communication all the times, andthe communication path is set up in response to the call from the userterminal. When the communication path is set up, the order slip data aretransmitted collectively, and the host computer 1 which receives theorder slip data then carries out the admission processing whilereturning the admission notice to the user terminal. When there areother order slip data to be transmitted, the user terminal repeats thesimilar operations for the other order slip data. After the admissionnotices for all the order slip data are received, the communication pathis leased and the communication software and the ordering software areterminated.

[0028] In this operation sequence, the contents of the admissionprocessing and the admission notice depend on the required conditions ofthe system. For instance, it is possible to have a case of immediatelymaking an inventory check and a notification, a case of making aninventory check later on and a notification is made later on by thetransmission from the data center side, or a case in which thenotification based on the inventory check is omitted as the stock islarge enough to eliminate any possibility for the shortage of the stock.In a case of involving the lot drawing as in a case of the ticketreservation, the winners are going to be notified afterwards.

[0029]FIG. 4A shows an example of the order entry system in thevideotex, in which the videotex terminal 5 replaces the personalcomputer 4 in FIG. 3A as the user terminal. The similar remarks asmentioned above for the network 4 in FIG. 3A also apply in this case. Inthe videotex of FIG. 4A, unlike the order receiving system of FIG. 3A,all the screen displays at the videotex terminal 5 are transmitted fromthe data center in response to the requests made from the videotexterminal 5. Therefore, the production of the order slip is also carriedout by the dialogue with the data center.

[0030]FIG. 4B shows an operation sequence in this videotex of FIG. 4A,in which the videotex terminal 5 is activated first, and then thecommunication path is set up with respect to the host computer 1. Inresponse, the initial display is transmitted from the host computer 1,and then using the ordering display transmitted from the host computer 1in response to the ordering display retrieval request, the order dataare entered and the accordingly updated ordering display is transmittedfrom the host computer 1. Then, the host computer 1 which receives theorder data then carries out the admission processing while transmittingthe admission notice. After the admission notice is received, thecommunication path is leased and the videotex terminal 5 is terminated.

[0031] By comparing these cases of FIG. 3B and FIG. 4B, the orderingsoftware is required on the user terminal side in a case of FIG. 3B, butthe appropriate ordering software may be different according to theconditions of the data center side for receiving the orders, so that theburden on the user can be heavy in a case of dealing with many orderreceivers. In addition, there is a need to modify the software at theuser terminal side in a case of changing the ordering item or theordering number. In contrast, in a case of FIG. 4B, the functionrequired on the user terminal side is a simple screen display alone, sothat the number of order receivers is of no concern as long as astandard protocol is used.

[0032] However, in this case, the communication path is maintained evenduring the production of the order slip, so that when the use of thecommunication network 4 costs the communication fee, the fee can behigher. Moreover, in a case of using the packet communication network,it can be inconvenient to have such a large amount of data transmissionfrom the data center.

SUMMARY OF THE INVENTION

[0033] It is therefore an object of the present invention to provide abook data service system in which the book data can be delivered by thebroadcasting and managed by a centralized management, only the necessarybook data can be selectively stored at each user terminal, the servicecan be charged according to the accesses to the book data actually made,and the feedback from the user to a data center can be made by simplyentering the feedback content into the displayed book data.

[0034] More specifically, it is an object of the present invention toprovide a book data service system in which the book data can bedelivered to any user located at any place promptly and economically,without causing the waste of the resources.

[0035] It is another object of the present invention to provide a bookdata service system in which the accurate charging for the use of thebook data can be made without requiring the transmission of the samedata content twice.

[0036] It is another object of the present invention to provide a bookdata service system capable of measuring the amount of utilization ofthe data delivered by the broadcasting by each user.

[0037] It is another object of the present invention to provide a bookdata service system in which the user is allowed to make a selection ofa desired data efficiently according to the advertisement for the bookdata, so as to improve the easiness in handling of the system using thedata delivery by the broadcasting.

[0038] It is another object of the present invention to provide a bookdata service system in which the feedback to the data center side can bemade without interrupting the book data reading operation of the user,the computer input operation for the collected feedback content isunnecessary at the data center side, and the flexible data input fromthe user terminal to the data center can be realized by requiring only alow communication cost to each user.

[0039] According to one aspect of the present invention there isprovided a book data service system, comprising: at least one datacenter including: data center computer for storing and managing bookdata; and broadcasting means for broadcasting the book data stored andmanaged by the data center computer according to a prescribedcommunication protocol using a synchronization control and an errorcorrection scheme suitable for data delivery by broadcasting withoutconfirmation from a receiving side; and a plurality of user terminals,each user terminal including: receiver means for receiving the book databroadcasted from the broadcasting means of the data center; userterminal computer for storing and managing the book data received by thereceiver means; and display means for displaying the book data storedand managed by the user terminal computer.

[0040] According to another aspect of the present invention there isprovided a method for providing a book data service, comprising thesteps of: storing and managing book data on a data center side by a datacenter computer of a data center; broadcasting the book data stored andmanaged by the data center computer according to a prescribedcommunication protocol using a synchronization control and an errorcorrection scheme suitable for data delivery by broadcasting withoutconfirmation from a receiving side; receiving the book data broadcastedfrom the data center at each user terminal; storing and managing thebook data on a user terminal side by a user terminal computer of theuser terminal; and displaying the book data stored and managed by theuser terminal computer on a display in an image of a book.

[0041] Other features and advantages of the present invention willbecome apparent from the following description taken in conjunction withthe accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

[0042]FIG. 1 is an illustration of an exemplary display in theBook-Metaphor system.

[0043]FIG. 2 is a list of navigation buttons provided in the display ofFIG. 1.

[0044]FIGS. 3A and 3B are diagrams of a system configuration and anoperation sequence in a conventional order receiving system using apersonal computer.

[0045]FIGS. 4A and 4B are diagrams of a system configuration and anoperation sequence in a conventional order entry system in the videotex.

[0046]FIG. 5 is a schematic block diagram of a system configuration forthe first embodiment of a book data service system according to thepresent invention.

[0047]FIG. 6 is a detailed block diagram of a configuration of the userterminal in the book data service system of FIG. 5.

[0048]FIG. 7 is a schematic block diagram of a modified systemconfiguration for the first embodiment of a book data service systemaccording to the present invention.

[0049]FIG. 8 is a detailed block diagram of an exemplary specificconfiguration of the user terminal in the book data service system ofFIG. 5.

[0050]FIG. 9 is a flow chart for the book data reception processing atthe user terminal in the book data service system of FIG. 5.

[0051]FIG. 10 is an illustration of an exemplary display in at the userterminal in the book data service system of FIG. 5.

[0052]FIG. 11 is a schematic block diagram of a system configuration forthe second embodiment of a book data service system according to thepresent invention.

[0053]FIG. 12 is a detailed block diagram of a configuration of the userterminal in the book data service system of FIG. 11.

[0054]FIG. 13 is a detailed block diagram of one specific configurationfor the second embodiment of a book data service system according to thepresent invention.

[0055]FIG. 14 is a flow chart for the operation in the specificconfiguration of FIG. 13.

[0056]FIG. 15 is an illustration of the data structure of the databasedata in the specific configuration of FIG. 13.

[0057]FIG. 16 is an illustration of a correspondence table used in thekey storage unit in the specific configuration of FIG. 13.

[0058]FIG. 17 is an illustration of an exemplary data for the table ofcontents used in the specific configuration of FIG. 13.

[0059]FIG. 18 is an illustration of an exemplary enciphered data for aspecific data content used in the specific configuration of FIG. 13.

[0060]FIG. 19 is an illustration of a common book data used in thespecific configuration of FIG. 13.

[0061]FIG. 20 is an illustration of the composed book data for the tableof contents used in the specific configuration of FIG. 13.

[0062]FIG. 21 is an illustration of an exemplary deciphered data for aspecific data content used in the specific configuration of FIG. 13.

[0063]FIG. 22 is an illustration of the composed book data for thespecific data content used in the specific configuration of FIG. 13.

[0064]FIG. 23 is a detailed block diagram of a modified configurationfor the second embodiment of a book data service system according to thepresent invention.

[0065]FIG. 24 is a flow chart for the operation in the modifiedconfiguration of FIG. 23.

[0066]FIG. 25 is an illustration of a correspondence table used in thekey storage unit in the modified configuration of FIG. 23.

[0067]FIG. 26 is an illustration of a utilization charge table used inthe charging processing unit in the modified configuration of FIG. 23.

[0068]FIG. 27 is a schematic block diagram of a system configuration forthe third embodiment of a book data service system according to thepresent invention.

[0069]FIG. 28 is a detailed block diagram of a configuration of the userterminal in the book data service system of FIG. 27.

[0070]FIG. 29 is a detailed block diagram of one specific configurationfor the third embodiment of a book data service system according to thepresent invention.

[0071]FIG. 30 is a diagram of the utilization level data used in thespecific configuration of FIG. 29.

[0072]FIG. 31 is an illustration of an exemplary display for the bookdata selection unit in the specific configuration of FIG. 29.

[0073]FIG. 32 is an illustration of an exemplary display at the bookdata display unit in the specific configuration of FIG. 29.

[0074]FIG. 33 is a detailed block diagram of a modified configurationfor the third embodiment of a book data service system according to thepresent invention.

[0075]FIG. 34 is a diagram of the utilization level data used in themodified specific configuration of FIG. 33.

[0076]FIG. 35 is a detailed block diagram of another modifiedconfiguration for the third embodiment of a book data service systemaccording to the present invention.

[0077]FIG. 36 is a detailed block diagram of still another modifiedconfiguration for the third embodiment of a book data service systemaccording to the present invention.

[0078]FIG. 37 is a detailed block diagram of a configuration of the userterminal in a book data service system according to the fourthembodiment of the present invention.

[0079]FIG. 38 is an illustration of an exemplary broadcast scheduletable used in the user terminal of the book data service system of FIG.36.

[0080]FIG. 39 is a flow chart for the storing of the book data at theuser terminal of the book data service of FIG. 37.

[0081]FIG. 40 is a flow chart for the storing of the broadcast scheduletable at the user terminal of the book data service of FIG. 37.

[0082]FIG. 41 is a detailed block diagram of one specific configurationof the book data service system according to the fourth embodiment ofthe present invention.

[0083]FIG. 42 is an illustration of an exemplary display of theadvertisement entry in the specific configuration of FIG. 41.

[0084]FIG. 43 is a diagrammatic illustration of the advertisement entrycodes stored in the advertisement entry code memory unit in the specificconfiguration of FIG. 41.

[0085]FIG. 44 is a diagrammatic illustration of the book data with thebook code which is used in the specific configuration of FIG. 41.

[0086]FIG. 45 is a diagrammatic configuration of the book data with theadvertisement entry code which is used in the specific configuration ofFIG. 41.

[0087]FIG. 46 is an illustration of an exemplary broadcast scheduletable used in the user terminal of the specific configuration of FIG.41.

[0088]FIG. 47 is a flow chart for the operation of the advertisemententry code comparison unit in the specific configuration of FIG. 41.

[0089]FIG. 48 is a flow chart for the operation of the book codematching unit in the specific configuration of FIG. 41.

[0090]FIG. 49 is a schematic block diagram of a system configuration forthe fifth embodiment of a book data service system according to thepresent invention.

[0091]FIG. 50 is a detailed block diagram of a configuration of the userterminal in the book data service system of FIG. 49.

[0092]FIG. 51 is a diagram of an operation sequence in the book dataservice system of FIG. 49.

[0093]FIG. 52 is a diagrammatic illustration of the book data formatused in the book data service system of FIG. 49.

[0094]FIG. 53 is an illustration of an exemplary display in at the userterminal in the book data service system of FIG. 49.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0095] First, the main features of the book data service systemaccording to the present invention will be summarized briefly.

[0096] In the book data service system according to the presentinvention, the book data are presented in an image of a book, anddelivered to each user terminal by the broadcasting. Here, the userterminal is permanently equipped with means for managing the book dataand means for displaying the book data which are common to all the userterminals, and only the book data produced according to the prescribedrules are delivered. In this manner, it becomes possible to reduce theamount of data to be delivered, while the display mode and the operationscheme are standardized from the point of view of a user such that thehandling of the system becomes easier for the user.

[0097] Of course, the degrees of freedom for the manner of expressionand the manner of operation depending on the type of the book should beretained, but the identical display and operations are to be used forthe same purpose. For example, it is normally preferable to use theexpression in an image of a double sided book as shown in FIG. 1, butthe expression in an image of a single sided book may also be requiredin a case involving many wide figures and tables. These different typesof expressions are to be controlled by the same program for the sameoperations to realize the functions such as the page turning and theindex search.

[0098] Also, all the books including those which utilize only the basicfunction of still image display, as well as those which contains thespeeches or dynamic images are handled by the same program, with theonly difference concerning whether or not to provide call up buttons forthe speeches or dynamic images on the book data display, such that thefunctions common to various books such as the page turning and the indexsearch can be realized by the same operations. In addition, themanagement data format and menu configuration for enabling the searchand selection of the book data are set to be uniform.

[0099] The protocol for the book data broadcasting is that which iscapable of automatic pull in at the terminal side and using the errorcorrection codes, as it is impossible to make a response or are-transmission request from the terminal side. Also, in order toexplicitly indicate the start and end of each book data, identifiers forindicating the top, middle, and bottom of the book data are provided atprescribed positions among the synchronization codes. In addition, thebook codes or field codes, the book title, the author name, thepublisher name, etc. which are necessary for the management of the bookdata are also provided at prescribed positions in the book data.

[0100] As the goal of the present invention is to make a large amount ofbook data freely accessible to the user, the book data broadcasting fromthe data center is not repeated in short period of time, and there-broadcasting is limited to those which are absolutely necessary asthe measure against the uncorrectable burst errors, and those of thepopular book data after some period of time since the initialbroadcasting, while the terminal is equipped with a large capacity filememory such that a large number of book data can be stored and managed.Here, it is preferable to make at least one re-broadcasting of each bookdata, but any further re-broadcasting is to be carried out according tothe aerial state at a time of the broadcasting or a number of requestsfrom the users.

[0101] In conjunction with the deliver the book data by thebroadcasting, the following two problems arise. One is a problem of howto charge the user, which is relevant in a case of providing the bookdata in exchange to the fee. The other is a problem that the shortage ofthe file memory capacity can be caused easily if all the broadcastedbook data are to be stored, as an enormous amount of book data are to bedelivered day and night.

[0102] As a solution to the problem of charging, it is possible toconsider the scheme for charging a uniform fee per month from all thesubscribers regardless of the amount of accesses actually made, but thecharging according to the amount of accesses actually made is morereasonable for the users as well as more rewarding for the author. As ascheme for charging an access to the book data delivered by thebroadcasting, there is a scheme in which the book data are encipheredand a deciphering key request is transmitted automatically from theterminal to the data center whenever the user calls up the book data inresponse to which the deciphering key is returned while charging thefee, and a scheme in which the record of the deciphering operationscarried out is inspected by the regular inspection by an inspectionworker or the remote inspection from the data center. Here, in a case ofproviding means for communicating feedbacks from the users to the datacenter as will be described below, the end-to-end communication througha public communication network between each terminal and the data centeris necessary, and such communication means can also be utilized for thesupply of the deciphering key or the remote inspection described above,so that the investment required for the purpose of the charging can bereduced.

[0103] As the solution to the problem of the book data amount, there isa scheme for selectively storing only those book data whose storing hasbeen reserved by the user in accordance with the broadcast scheduledelivered in advance. Here, unlike the reservation by specifying time asin the conventional VTR recording reservation, the reservation is to bemade by specifying a book code assigned to each book data such thatthose book data having the book codes coinciding with reserved bookcodes are stored.

[0104] This reservation scheme is adopted because the reservation bytime is less reliable in view of its accuracy as the book data of anormal size can be broadcasted in a very short period of time when oneTV broadcasting channel is exclusively used for the transmission of thebook data for example, and because the book code is necessary even whenthe reservation by time is adopted as it is necessary to store the bookdata with some margins before and after the significant portion and takeout the significant portion from the stored data afterwards.

[0105] In addition, the reservation by the book code has an advantage inthat it is possible to deal with the change of the broadcasting time dueto the aerial state or the convenience of the data center. It is alsouseful in preventing the redundant storage of the already stored bookdata in a case of the re-broadcasting. Of course, it is also possible tolimit the reception time range along with the reservation by the bookcode from a point of view of saving the power. It is to be noted herethat there is no need for the user to be conscious about the book codeitself, and the reservation by the book code is made automatically asthe user specifies the desired books on the broadcast schedule deliveredto the user.

[0106] Furthermore, the book data service system according to thepresent invention also provides means for communicating feedbacks fromthe user terminal to the data center. More specifically, the user entryspaces or the choice indicating columns are provided in the book data,and the data entered or selected by the user at these user entry spacesor the choice indicating columns are automatically edited in theprescribed format and transmitted to the data center as soon as the datatransmission is specified by the user after the entry or the selectionof the data. Here, more than one data centers may be involved, so thatthe subscribed network type or number of the data center to which thefeedback is to be transmitted is registered in the book data by theprescribed format, and the connection of the data center and the userterminal is automatically made according to the registered information.In response to the feedback received, the data center at least returnsthe receipt notice immediately, such that the receipt result can bedisplayed at the user terminal side. In a case of returning the resultof the processing at the data center, it is returned along with thereceipt notice immediately if possible, or it is returned separately bythe call initiated by the data center as in a case of the ticketreservation involving the drawing in which it is impossible to return itimmediately.

[0107] Among these features of the book data service system according tothe present invention, the book data delivery using the broadcasting isa feature common to all the embodiments described below, while thefeatures concerning the charging, the storing reservation, and thefeedback communication are mutually compatible with each other, so thatit is possible to construct the system incorporating all of thesefeatures simultaneously.

[0108] Now, the first embodiment of the book data service systemaccording to the present invention will be described in detail.

[0109] In this first embodiment, the book data service system has asystem configuration as shown in FIG. 5, which comprises: a data center50 equipped with a computer 51 containing a book data storage unit 52for storing the book data and a book data broadcast management unit 53for managing the mroadcasting of the book data, and a broadcastingfacility 54 for executing the broadcasting of the book data; and aplurality of user terminals 55, each containing a computer 56 formanipulating the book data and a broadcast recevier 57 for receiving thebroadcast from the data center 50. Here, it is also possible to providemore than one data centers 50 in which case the broadcast receiver 57 ofthe user terminal 55 is required to have a function for selecting thefrequency or other characteristic of the broadcasting radio waves fromeach data center 50. Also, the broadcasting is not necessarily limitedto the radio broadcasting, and can be a wire broadcasting in a manner ofthe cable TV.

[0110] The user terminal 55 has a detailed configuration as shown inFIG. 6, where the broadcast receiver 57 includes a channel selection anddemodulation circuit 67 connected with an antenna or a CATV connectorfor removing a broadcasting carrier from the received signals to obtaindemodulated signals, a data signal separation circuit 68 for separatingthe error correction encoded data from the demodulated signals, and anerror correction circuit 69 for applying an error correction to theerror correction encoded data to obtain the error corrected datarepresenting the received book data. On the other hand, the computer 56includes a book data storage unit 61, a book data management unit 62,and a book data display unit 63, while the computer 56 is also equippedwith peripheral devices such as a large capacity file memory 64, anoperation input unit 65, and a display unit 66, which are utilized instoring and displaying the book data.

[0111] Here, the large capacity file memory 64 is usually realized by ahard disk device, but it can be realized by the other memory device aslong as sufficient memory capacity and memory access performance can beprovided. The operation input unit 65 usually incorporates a keyboardand a mouse, but it may also incorporate the other input device such asa pen input device, or a touch panel display to be provided integrallywith the display unit 66. It is also noted that these peripheral devicescan be provided within the main body of the computer 56 if desired.

[0112] This system shown in FIG. 5 and FIG. 6 operates as follows.First, the data delivery from the data center 50 is achieved bysupplying the book data stored in the book data storage unit 52 of thecomputer 51 to the broadcasting facility 54 in accordance with thebroadcast schedule registered in advance in the book data broadcastmanagement unit 53, and then sequentially broadcasting the supplied bookdata from the broadcasting facility 54. At this point, the broadcastedsignals are those in which the digital data are divided into appropriatesizes, the error correction codes and the synchronization codes areadded, and then superposed onto the broadcast carrier, as in a case ofthe multi-channel character broadcasting.

[0113] At the user terminal 55, the broadcasted signals are received bythe broadcast receiver 57, and the error corrected data are supplied tothe computer 56 as described above. In the computer 56, the main body ofthe book data is taken out from the received data by separating themanagement data, and stored into the large capacity file memory 64 bythe book data storage unit 61, while at the same time, the managementdata such as the book title, author name, field name, etc. are taken outand and supplied to the book data management unit 62 along with a filename of the stored book data, in response to which the book datamanagement unit 62 updates the book management data. The book managementdata are also stored in the large capacity file memory 64.

[0114] The presentation of the stored book data is made in such a mannerthat, in response to an access to the book data management unit 62 madeby the user by using the operation input unit 65, the book datamanagement unit 62 reads out the book management data from the largecapacity file memory 64, and then produces and displays the book menu onthe display unit 66. In this display of the book menu, the selection ofthe book data can be made easier by narrowing the books listed on themenu by specifying the author name, the field of the book, etc. as thekey data. Then, as the desired book is selected by the user on the bookmenu, the book data management unit 62 supplies the file name of theselected book data to the book data display unit 63, and the book datadisplay unit 63 reads out the corresponding book data from the largecapacity file memory 64 and displays the front cover of the read outbook data on the display unit 66. Thereafter, the display of the bookdata in accordance with the usual operations and display functions ofthe Book-Metaphor is going to be carried out.

[0115] Here, the broadcasting facility 54 of the data center 50broadcasts the book data according to the prescribed communicationprotocol suitable for the data delivery by the broadcasting, in whichthe synchroinization control and the error correction can be madewithout the confirmation signal from the user terminal 55, by adding thecontrol data and the error correction codes, and appropriatelymodulating the book data. In correspondence, the broadcast receiver 57of the user terminal 55 receives the broadcasting signals of the radiobroadcasting or the wire broadcasting, and extracts the data to besupplied to the computer 56 according to the prescribed communicationprotocol. In a case of the radio broadcasting, the communicationprotocol having a sufficient redundancy level such as that of themulti-channel character broadcasting as mentioned above.

[0116] It is also to be noted that the book data storage unit 52 of thecomputer 51 may not necessarily be provided in the same building as thebroadcasting facility 54, but the book data broadcast management unit 53should be provided in a vicinity of the broadcasting facility 54, andthe book data storage unit 52 and the book data broadcast managementunit 53 can be connected either by the communication line or bytransportation of the data storing medium.

[0117]FIG. 7 shows an alternative system configuration for this firstembodiment, in which the CATV is utilized for the deliver of the bookdata. In this case, the data center is equipped with a CATV broadcastingfacility 71 connected with the broadcast receiver 57 of each userterminal 55 through a CATV cable 72. The rest is similar to the systemconfiguration of FIG. 5. In this case, the communication protocol of themulti-channel character broadcasting is also suitable because of theaffinity with the CATV broadcasting mechanism. However, in this case,the reliability of the data transmission is high because of the wirebroadcasting, so that the more efficient communication protocol with thelower redundancy level may be used if desired.

[0118] Here, as a communication scheme similar to the wire broadcasting,the off-talk communication utilizing the subscriber lines of thetelephone or ISDN may also be used, in which case the book data can betransmitted instead of the usual facsimile data within the communicationprotocol of the off-talk facsimile communication. Also, by using thedigital off-talk communication, it becomes possible to make the datatransmission at a higher speed. It is to be noted however that, by usingthe telephone subscriber lines or the digital subscriber lines of 64kb/s, the transmission of the book data for one book can take as long asseveral minutes to several tens of minutes, so that the use of thesetransmission lines may be limited for the special purposes until thehigher speed ISDN becomes widely available.

[0119] The user terminal 55 shown in FIG. 6 can have a more specificconfiguration as shown in FIG. 8, in which the radio antenna or the CATVwire connector is not explicitly shown. In the broadcast receiver 57,the channel selection and demodulation circuit 67 selects anddemodulates the channel such as that of the multi-channel characterbroadcasting for example, and the data signal separation circuit 68extracts the significant data. In a case of the multi-channel characterbroadcasting, the character signals can be separated from the signalwaveform of the vertical interval signals. Then, the error correctioncircuit 69 carries out the error correction using the error correctioncodes of the received data, and the obtained data are supplied to thecomputer 56.

[0120] The computer 56 comprises a processor (CPU) 81, a ROM 82 and aRAM 83 for storing programs, etc., a broadcast receiving interface 84for receiving received data from the broadcast receiver 57, a displaycontroller 85 for controlling the display on the display unit 66, a harddisk (HD) controller 86 for controlling-data input/output of the harddisk device 64A, a floppy disk (FD) controller 87 for controlling datainput/output of the floppy disk device 64B, a keyboard interface 88 forcontrolling input from the keyboard 65A, and a mouse interface 89 forcontrolling input from the mouse 65B.

[0121] When the book data receiving function of the book data displayprogram for realizing the operation of the book data display unit 63 ofFIG. 6 is active on the computer 56, the book code of the received datais checked, and the received data are written into the hard disk device64A if the received data are new data, while updating the list of thebooks accordingly. When the book data reception becomes abnormal in amiddle, the received data are discarded and the incoming data areignored until the next new book data arrive.

[0122] Here, the book with a large data amount has a higher chance ofencountering the radio obstruction in a middle, so that it is possibleto carry out the storing in units of chapters or pages, such that thenormally received chapters or pages can be stored even after the bookdata reception is interrupted in a middle as parts of the incompletelyreceived book, and the missing parts can be supplemented afterwards bythe book data reception of the re-broadcasting. In this case, it isnecessary to define in advance the data structure in which the storingunits such as chapters or pages can be re-arranged on the memory.

[0123] In this case, the book data reception processing at the computer56 including the data supplementing can be carried out according to theflow chart of FIG. 9 as follows.

[0124] Namely, the book code is received (step S1), and the list of thealready received books is searched through (step S2) to judge whetherthe received book data is the newly received book or not (step S3). In acase of the newly received book, the book data is received and stored(step S4), while judging if there is any missing data or not (step S5).If there is no missing data, the received book data is classified as thecompletely received book data (step S6), and the book list is updated toadd the entry for this book data (step S7). If there is some missingdata, the received book data is classified as the incompletely receivedbook data (step S8), and then the re-broadcasting is awaited as anopportunity for supplementing the book data.

[0125] When the received book data is not the newly received book,whether it is the already received book which is classified as theincompletely received or not is judged (step S9). If it is not theincompletely received book data, it implies that it is the alreadyreceived book, so that the received book data is discarded (step S10).If it is the incompletely received book data, the book data is receivedand stored (step S11), while judging if there is any missing data or not(step S12). If there is no missing data, the received book data isclassified as the completely received book data (step S13), and the booklist is updated to add the entry for this book data (step S14).

[0126] If there is some missing data, whether it is possible tosupplement the missing data from the already received data or not isjudged (step S15). If it is possible, the missing data of the book datais suppledmented by the already received data (step S16), and thereceived book data is classified as the completely received book data(step S17) while the book list is updated to add the entry for this bookdata (step S18). If it is not possible, the missing data of the bookdata is suppledmented as much as possible by the already received data(step S19), and the received book data is classified as the incompletelyreceived book data (step S20), and then the re-broadcasting is awaitedas an opportunity for supplementing the missing data.

[0127] As a simpler alternative scheme, the book can be formed in numberof volumes, and the storing and discarding of the book data can beallowed only in units of volumes, so as to eliminate the intermediatestate such as the incompletely received state.

[0128] When the user reads the book, the book data display program iscalled up as a front task. In this book data service system, the libraryfunction to manage the books is indispensable as a large number of booksare to be stored. To this end, as shown in FIG. 10, the book datadisplay can incorporate a library button 100 as one of the navigationbuttons. In the reading operation, when this library button 100 isspecified by the mouse 65B, the list of the books stored in the filememory such as the hard disk device 64A is displayed. Then, when onebook title on the list is specified by the mouse 65B, the correspondingbook data is read out from the file memory and displayed, starting fromthe front cover. Thereafter, the user can read any desired page of thisbook by specifying appropriate one of the navigation buttons, the tableof contents, tags, and labels by the mouse 65B to control the displayappropriately.

[0129] It is more convenient to provide the user terminal of this bookdata service system in a portable type, using a portable computer forthe computer 56. In this case, it is naturally preferable to utilize thecompact and easy to operate portable computer suitable for the purposeof reading the book. Even in a case of the desk top type user terminal,in a case of the frequency use, the integral installation of thebroadcast receiver 57 or the simplification of the keyboard or pointingdevice may be beneficial.

[0130] As described, according to this first embodiment, the book dataare delivered by the broadcasting, so that the book data can be obtainedby any user located at any place, quickly and cheaply, and as no memorymedium is required for the purpose of selling the book data, it isadvantageous in saving the resources and the space.

[0131] In this book data service system, the data center possesses anumber of book data produced at the center computer or other computers,and supplies the book data to the broadcasting facility sequentially,while the broadcasting facility carries out the broadcasting similar tothe multi-channel character broadcasting for example, by addingnecessary data and modulating the book data according to thecommunication protocol suitable for the data delivery by thebroadcasting. In the communication protocol of the multi-channelcharacter broadcasting, it is assumed that there is no confirmationsignal from the receiver side, and therefore the sufficient redundancyis provided in the synchronization codes for determining the position ofthe significant data and the error correction codes for making the dataerror correction, so that it is suitable for the data delivery by thebroadcasting.

[0132] The multi-channel character broadcasting is only an example ofthe communication protocols that can be utilized in this book dataservice system, and any communication protocol can be utilized as longas it is capable of making the data transmission at the sufficientreliability without using the confirmation signal from the receiverside. However, in a case of using the radio broadcasting, the receptionerror due to the bursty radio obstruction is unavoidable. There are alsopossibilities for failing to receive the desired data in a case offorgetting to turn on the power at the receiver side, or in a case ofusing the computer in which the data reception cannot be handledsimultaneously with the other processing such as the book data displayfor example. Consequently, in operating the system, it is necessary totake these possibilities in consideration and provide there-broadcasting of the same book data after some time interval forinstance. Here, in the multi-channel character broadcasting, the dataare transmitted by utilizing the vertical retrace interval in the TVbroadcasting signals, so that when the demand for the broadcasting ofthe book data increases, the allocation of the dedicated frequencychannel may be considered.

[0133] On the user terminal side, the received book data aredemodulated, and the extraction of the significant data and the dataerror correction are made according to the prescribed communicationprotocol, and the obtained book data are stored in the file memory atthe computer. Consequently, when the single task OS is used, the datareception and the other processing cannot be carried out simultaneously,but when the multi-task OS is used, the task concerning the datareception in the book data display program can be set in a running stateall the times in the background, such that the desired book data can bereceived without a failure. Here, when a plurality of computers areconnected through the LAN, and one of them is made to be a book datareceiving server implementing the multi-task OS and the book datareceiving function, the book data reception failure can be prevented forthe other computers as the other computers can copy the necessary bookdata from the book data receiving server when they are idle. If theproblem related to the performance such as the display speed is ignored,it is also possible to adopt the scheme in which the access is made tothe file memory of the book data receiving server whenever the needarises.

[0134] At a time of the data storing, the book data storage unit 61checks the received data automatically, so as not to store the alreadystored book data again in a case of the re-broadcasting. Also, by usingthe book data management unit 62 for allowing the user to make aselection by displaying the list in which the books stored in the filememory are appropriately classified, and the book data display unit 63for realizing the book functions such as the page turning on theselected book data, the desired book can be selected and displayedaccording to the user's input.

[0135] Thus, in this book data service system, any user at any place canobtain the book data quickly and cheaply, and read the desired book datawhenever the user wishes. Moreover, the file memory can store a largenumber of book data, while the unnecessary book data can be deleted tomake room for new book data, so that the saving of the resource andspace can be achieved effectively.

[0136] Next, the second embodiment of the book data service systemaccording to the present invention will be described in detail.

[0137] In this second embodiment, the book data service system has asystem configuration as shown in FIG. 11 where, in addition to thesystem configuration of FIG. 5 described above, the data center 50A andthe user terminal 55A are equipped with communication devices 112A and112B, respectively, which are capable of making one-to-one communicationthrough a communication network 111.

[0138] Moreover, the computer 51A of the data center 50A furtherincludes a deciphering key returning unit 113 connected with thecommunication device 112A which returns the deciphering keycorresponding to the requested book data in response to the decipheringkey request made from the user terminal 55A, and a charging unit 114connected with the deciphering key returning unit 113 which calculatesthe charge for each user.

[0139] The user terminal 55A has a detailed configuration as shown inFIG. 12 where the configuration of FIG. 6 described above is modifiedsuch that the book data display unit 63A includes the book datainspection unit 121 for inspecting whether the book data are encipheredor not, and the computer 56A further including a deciphering keyacquiring unit 122 for acquiring the deciphering key via thecommunication device 112B and a deciphering unit 123 for deciphering theenciphered book data, both of which are connected with the book datadisplay unit 63A. Here, the deciphering unit 123 may be provided as anexternal dedicated decoder if desired.

[0140] This system shown in FIG. 11 and FIG. 12 operates similarly as inthe first embodiment described above as far as the delivery, reception,and storing of the book data are concerned. However, the operation at atime of displaying the book data is different as follows.

[0141] Namely, at a time of the book data display, first, the desiredbook is selected at the book data management unit 62 and notified to thebook data display unit 63A, which reads out the corresponding book datafor the selected book from the large capacity file memory 64. Then, thebook data inspection unit 121 of the book data display unit 63A inspectswhether the read out book data is enciphered or not. If it is notenciphered, the displaying of the book data on the display unit 66 isstraightforwardly carried out by the book data display unit 63A. On theother hand, in a case it is enciphered, the user is inquired as to theneed for deciphering this enciphered book data. When the user refusesthe deciphering, the message to ask for the selection of the other page,chapter, or book is displayed. When the user requests the deciphering,the deciphering key acquiring unit 122 produces the deciphering keyrequest and transmits the produced deciphering key request to the datacenter 50A via the communication device 112B.

[0142] In response to the deciphering key request received via thecommunication device 112A, the deciphering key returning unit 113 of thedata center 50A returns the appropriate deciphering key via thecommunication unit 112A, and the deciphering key received via thecommunication unit 112B is given to the book data display unit 63Athrough the deciphering key acquiring unit 122. Then, the book datadisplay unit 63A supplies the acquired deciphering key along with thebook data to be deciphered to the deciphering unit 123, which deciphersthe book data by using the acquired deciphering key and returns thedeciphered book data to the book data display unit 63A. The book datadisplay unit 63A then carried out the display of the deciphered bookdata on the display unit 66.

[0143] Here, when the deciphering key is not free and charged, the feecharged for the deciphering key is also indicated at a time of inquiringthe need for the deciphering. In a case of returning the chargeddeciphering key, the charging unit 114 of the data center 50A chargesthe fee to the user. The book data is usually not enciphered entirely,and the front cover, the table of contents, or the introduction section,etc. is usually left unenciphered so as to be enable the user tocomprehend the outline of the book, and the inquiry of the need fordeciphering is not made at a time of displaying these unencipheredpages, but made only when the display of the enciphered pages isrequested. Once the deciphering key is acquired, there is no need tore-acquire the deciphering key while displaying the effective range ofthe acquired deciphering key, but it is not necessary for one book to beable to decipher by only one deciphering key and the differentdeciphering keys may be required in units of chapters, for example. Insuch a case, it is necessary to request the deciphering key at every newchapter to be displayed.

[0144] Whether or not to allow the user terminal 55A to store theacquired deciphering key and the deciphered book data after thedisplaying of the deciphered book data depends on the setting of thefees. In order not to allow the storing of the of the deciphering keyand the deciphered book data, it is necessary to make the internaldesign of the user terminal program to be not publicly disclosed, and tosupply the user terminal program from the book data service provider'sside.

[0145] In further detail, according to this second embodiment, the bookdata service system has a detailed configuration as shown in FIG. 13,which realizes the charging processing according to the databaseutilization and management scheme according to the present invention. Inthis system, there are more than one user terminals even though only oneuser terminal is shown in FIG. 13, and each user terminal is identifiedby a user registration number.

[0146] The system of FIG. 13 generally comprises a data center sidesystem 130 and a user terminal side system 140, which are mutuallyconnected through communication lines 151 and 152.

[0147] The data center side system 130 comprises: a data base datastorage unit 131 for storing database data; a data enciphering unit 132for, enciphering different items of the database data stored in thedatabase data storage unit 131 by different keys; a key storage unit 133for storing a key for each item of the database data; a datatransmission unit 134 for transmitting the enciphered database data andkey data to the user terminal side system 140; a display requestreceiving unit 135 for receiving a data content display request from theuser terminal side system 140; a key retrieval unit 136 for retrievingthe key for an item specified by the data content display request fromthe key storage unit 133 and transmitting it to the data transmissionunit 134, while also generating a processing signal for a chargingprocessing; a charging processing unit 137 for carrying out the chargingprocessing in response to the processing signal from the key retrievalunit 136; and an individual utilization data management unit 138 forstoring charging data for each user.

[0148] Here, the data transmission unit 134 attaches an item number foreach item of the database data at a time of transmitting the enciphereddatabase data, and at a time of transmitting the key data obtained fromthe key retrieval unit 136, it also transmits a signal indicating thatit is the key data along with the key data. The display requestreceiving unit 135 transmits the item number requested to be displayedand the user registration number of the requesting user to the keyretrieval unit 136 when the data content display request is receivedthrough the transmission line 152. The key retrieval unit 136 reads outthe key data corresponding to the item number requested to be displayedfrom the key storage unit 133, and transmits the user registrationnumber to the charging processing unit 137, while transmitting the readout key data to the data transmission unit 134. The individualutilization data management unit 138 stores the a number of utilizeddatabase items in correspondence to each user registration number. Then,the charging processing unit 137 reads out the number of utilizeddatabase items for the requesting user from the individual utilizationdata management unit 138 according to the user registration numberreceived from the key retrieval unit 136, adds one to the read outnumber, and stores the new number of utilized database items into theindividual utilization data management unit 138.

[0149] On the other hand, the user terminal side system 140 comprises: adata receiving unit 141 for receiving the database data and the key datatransmitted from the data center side system 130; a data storage unit142 for storing the received database data; a data deciphering unit 143for deciphering the database data stored in the data storage unit 142 byusing the received key data; a common book data storage unit 144 forstoring common book data indicating data common to all the book datasuch as the format data; a book data composition unit 145 for obtainingthe book data by composing the deciphered database data and the commonbook data; a book data display unit 146 for displaying the composed bookdata on a display; a data operation input unit 147 for entering dataretrieval operation or data content display request operation by theuser; an input control unit 148 for converting the signals entered atthe data operation input unit 147, recognizing the content of theentered operation, and transmitting the converted signals to a datacontrol unit 149 or a display request transmission unit 150 to bedescribed below according to the recognized content; a data control unit149 for controlling the data storage unit 142 according to the enteredoperation when the entered operation is the data retrieval operation;and a display request transmission unit 150 for transmitting the datacontent display request to the data center side system 130 when theentered operation is the data content display request operation.

[0150] Here, the data receiving unit 141 transmits the database data byattaching the item number to each item to the data storage unit 142 whenthe database data is received, or transmits the key data to the datadeciphering unit 143 when the received data contains the signalindicating that it is the key data. The data storage unit 142 stores thedatabase data transmitted from the data center side system 130 with theitem number as an index, and transmits the database data to the datacontrol unit 149 by restoring the data structure according to the itemnumbers, while transmitting the database data corresponding to the itemnumber specified from the data control unit 149 to the data decipheringunit 143. Also, the data deciphering unit 143 transmits the deciphereddatabase data to the book data composition unit 145 by deciphering theenciphered database data by using the received key when the key data issupplied from the data receiving unit 141, or transmits the receiveddatabase data as it is to the book data composition unit 145 when no keydata is supplied from the data receiving unit 141. The display requesttransmission unit 150 memorizes the user registration number, andtransmits the received item number along with the user registrationnumber to the data center side system 130 when the item number isreceived from the input control unit 148.

[0151] Now, the data retrieval operation and the data content displayrequest operation in this book data service system of FIG. 13 will bedescribed. The data control input unit 147 is equipped with an inputdevice such as a keyboard containing a cursor key. In this embodiment,the data to be displayed is the book data, so that the operation forspecifying the display of the next page or the previous page is carriedout as the data retrieval operation. The operation for specifying thedisplay of the next page or the previous page can be made by pressing“→” key or “←” key for example. Also, the data content display requestoperation is an operation for requesting the display of the data contentby deciphering the data, which can be made by entering the item numberof the item to be deciphered and displayed from the keyboard forexample. Here, at a time of the system activation, the user registrationnumber is to be entered from the keyboard of the data operation inputunit 147. In this manner, various input operations are made at the dataoperation input unit 147, and in response the input control unit 148transmits the commands for the next page or the previous page to thedata control unit 149 when the entered signal is “→” or “←”, ortransmits the item number to the data control unit 149 and the displayrequest transmission unit 150 when the entered signal is the itemnumber, or transmits the user registration number to the display requesttransmission unit 150 when the entered signal is the user registrationnumber.

[0152] The data control unit 149 memorizes the item number of thecurrently displaying book data, and the data structure received from thedata storage unit 142, and updates the memorized item number to the itemnumber greater by one when the next page command is received, or to theitem number smaller by one when the previous page command is received,or to the received item number itself when the item number is received,and transmits the memorized item number to the data storage unit 142. Asan item number for the data to be initially displayed, the item numberof the table of contents is memorized, and this item number istransmitted from the data control unit 149 to the data storage unit 142.

[0153] Now, the operation in this embodiment of FIG. 13 is carried outaccording to the flow chart of FIG. 14 as follows.

[0154] First, the database data stored within the database data storageunit 131 of the data center side system 130 is enciphered by usingdifferent keys for different items at the data enciphering unit 132, andthe key for each item is stored in the key storage unit 133 (step S101).The enciphered database data are then transmitted from the datatransmission unit 134 to the data receiving unit 141 of the userterminal side system 140 and stored in the data storage unit 142. (stepS102).

[0155] At this point, in a case the data content display requestoperation is made at the data operation input unit 147 of the userterminal side system 140, the data content display request istransmitted to the data request receiving unit 135 of the data centerside system 130 through the input control unit 148 and the displayrequest transmission unit 150. As a result, the key retrieval unit 136retrieves the key corresponding to the requested item from the keysstored in the key storage unit 133, and transmits the processing signalto the charging processing unit 137. The charging processing unit 137then carries out the charging processing in response to the processingsignal (step S103). Then, the data on the number of utilized databaseitem is stored in the individual utilization data management unit 138.After the transmission of the processing signal, the key retrieval unit136 transmits the retrieved key to the data transmission unit 134, andthe data transmission unit 134 transmits this key as the key data to thedata receiving unit 141 of the user terminal side system 140 (stepS104).

[0156] The data receiving unit 141 which received the key data thentransmits the received key data to the data deciphering unit 143. On theother hand, the data control unit 149 which received the data retrievaloperation command from the input control unit 148 calculates the itemnumber of the data to be displayed and transmits it to the data storageunit 142, and then data storage unit 142 reads out the correspondingdatabase data from the stored database data and transmits it to the datadeciphering unit 143. Then, the data deciphering unit 143 deciphers thedatabase data supplied from the data storage unit 142 by using the keydata supplied from the data receiving unit 141 (step S105). Then, thebook data composition unit 145 composes the book data from the databasedata deciphered by the data deciphering unit 143 and the common bookdata stored in the common book data storage unit 144, and the obtainedbook data is displayed at the book data display unit 146 (step S106).

[0157] Next, the further detailed concrete examples concerning theembodiment of FIG. 13 will be described.

[0158] The database data storage unit 131 on the data center side system130 stores a plurality of database data, and each database data is goingto be transmitted to the data enciphering unit 132 in the data structureshown in FIG. 15, where each rectangle represents an item, and each itemcorresponds to one spread page of the book data.

[0159] First, the database data in the data structure of FIG. 15 istransmitted from the database data storage unit 131 to the dataenciphering unit 132. The data enciphering unit 132 then generatesdifferent enciphering keys for different items of the database data byusing the random number, enciphers the data content of each item exceptfor the item of the table of contents, and transmits the enciphered datato the data transmission unit 134 by attaching the item number to eachitem, while also transmitting a correspondence table of the encipheringkeys used and the item numbers to the key storage unit 133. An exampleof the correspondence table stored in the key storage unit 133 is shownin FIG. 16. Then, the data transmission unit 134 transmits theenciphered database data to the data receiving unit 141 of the userterminal side system 140 through the transmission line 151.

[0160] The data receiving unit 141 then receives the enciphered databasedata, and transmits it to the data storage unit 142. The data storageunit 142 stores the database data transmitted from the data receivingunit 141 with the item number of each item as an index, and thenproduces the data structure of the database data according to the itemnumbers and transmits it to the data control unit 149. At this point,the data storage unit 142 also stores the data representing the table ofcontents as shown in FIG. 17, as well as the enciphered data such asthat shown in FIG. 18 representing the data content of the item number“2A” for example.

[0161] The data control unit 149 memorizes the received data structureand transmits the item of the table of contents to the data storage unit142 as the item number of the data to be initially displayed. Then, thedata storage unit 142 reads out the data content of this item as shownin FIG. 17 and transmits it to the data deciphering unit 143. At thedata deciphering unit 143, the deciphering is not carried out as thereis no key data received, and the data content as shown in FIG. 17 istransmitted as it is to the book data composition unit 145. The bookdata composition unit 145 then reads out the common book data as shownin FIG. 19 from the common book data storage unit 144, produces the bookdata by allocating the data content of FIG. 17 received from the datadeciphering unit 143 to the data content display portion of the commonbook data as shown in FIG. 19, and transmits the obtained book data tothe book data display unit 146. As a result, the book data display unit146 displays the book data as shown in FIG. 20 on its display.

[0162] Next, the user looks at the displayed table of contents, anddecides which item's data content should be displayed. Here, as anexample, a case of displaying the data content of the item number “2A”will be described. In this case, the user enters the item number “2A”from the keyboard of the data operation input unit 147 as a request fordeciphering and displaying the data content of the enciphered data. Inresponse, the input signal indicating this item number “2A” istransmitted to the input control unit 148, and the input control unit148 which received the input signal for “2A” transmits it to the datacontrol unit 149, while also transmitting it to the display requesttransmission unit 150 as an item number to be the deciphered anddisplayed. The display request transmission unit 150 which received thisitem number “2A” then transmits this item number “2A” along with theuser registration number such as “A1234” memorized in advance to thedisplay request receiving unit 135 of the data center side system 130.

[0163] The display request receiving unit 135 receives the item number“2A” and the user registration number “A1234” through the transmissionline 152, and transmits them to the key retrieval unit 136. The keyretrieval unit 136 then reads out the key “2” corresponding to the itemnumber “2A” according to the stored correspondence table shown in FIG.16, and transmits the user registration number “A1234” as the processingsignal to the charging processing unit 137, and then transmits the key“2” to the data transmission unit 134. The charging processing unit 137which received the processing signal indicating the user registrationnumber “A1234” then reads out the number of utilized database items forthis user registration number “A1234” such as a number “24” for examplefrom the individual utilization data management unit 138, adds on tothis number “24” to obtain a new number “25”, and stores this new number“25” as the number of utilized database items for the user registrationnumber “A1234” in the individual utilization data management unit 138.Then, the data transmission unit 134 transmits the received key “2”along with a signal indicating that it is the key data to the datareceiving unit 141 on the user terminal side system 140.

[0164] The data receiving unit 141 receives the key data for this key“2” through the transmission line 151, and transmits it to the datadeciphering unit 143. On the other hand, the data control unit 149 hasalready received the item number “2A” as the item number to bedeciphered and displayed from the input control unit 148, so that itrewrites the index of the currently displaying item from the “table ofcontents” to “2A”, and transmits it to the data storage unit 142. Thedata storage unit 142 which received this index of the item then readsout the enciphered data content of this item “2A” as shown in FIG. 18and transmits it to the data deciphering unit 143. The data decipheringunit 143 deciphers the enciphered data content of the item number byusing the key “2” transmitted from the data receiving unit 141. Theresulting deciphered data appears as shown in FIG. 21 for example. Then,the data deciphering unit 143 transmits the deciphered data content asshown in FIG. 21 to the book data composition unit 145. The book datacomposition unit 145 then reads out the common book data as shown inFIG. 19 from the common book data storage unit 144, produces the bookdata by allocating the data content of FIG. 21 received from the datadeciphering unit 143 to the data content display portion of the commonbook data as shown in FIG. 19, and transmits the obtained book data tothe book data display unit 146. As a result, the book data display unit146 displays the book data as shown in FIG. 22 on its display.

[0165] In the embodiment of FIG. 13 described above, variousmodifications are possible as follows.

[0166] For example, it is possible for the database to be distributed ata plurality of locations and the accesses to the distributed databasecan be made through the communication lines. Also, the content, theformat, or the data structure of the database data are optional.

[0167] The data units by which the enciphering is to be made are alsooptional and not necessarily the items as described above, such as theunits of the paragraphs, or any other specific groups. The encipheringscheme and the enciphering key generation scheme are also optional, andthe enciphering may be controlled to make no enciphering in units of thedata unit or to change the enciphering schemes in units of the dataunit. Also, the key storage unit 133 may store the enciphering schemeinstead of the enciphering key.

[0168] The connection state of the data center side system 130 and theuser terminal side system 140 for the purpose of data communication isalso optional, and can be any type of broadcasting such as the wirebroadcasting, the radio broadcasting, or the satellite broadcasting.Also, the data transmission unit 134 may attach any optional signalother than the signal for distinguishing the database data and the keydata.

[0169] The key retrieval unit 136 has been described as reading out thekey data corresponding to the received item number from the key storageunit 133 and transmitting the key data to the data transmission unit 134after the user registration number is transmitted to the chargingprocessing unit 137, but in general, the content to be received andtransmitted depends on the content transmitted from the display requestreceiving unit 135 and the content stored in the key storage unit 133.Also, instead of transmitting the key data to the data transmission unit134, the key data may also be transmitted to the data enciphering unit132 such that the key data are also enciphered and then transmitted. Asfor the content to be transmitted to the charging processing unit 137,it is not necessarily limited to the user registration number, and canbe the item number to be displayed for example.

[0170] The charging processing to be carried out at the chargingprocessing unit 137 may be the calculation of the fee itself rather thanthe updating of the number of utilized database items as describedabove, or the number to be added in updating the number of utilizeddatabase items can be provided in several levels depending on the amountof data to be displayed or the content of the data to be displayed. Thischarging processing may also be carried out on the other system terminalconnected through the communication network. The individual utilizationdata management unit 138 may also store the utilization history, thetype of the utilized database, the statistical data such as thefrequency of utilization of each type, etc. This individual utilizationdata management unit 138 may also be provided on the other systemterminal connected through the communication network.

[0171] The data receiving unit 141 has been described as transmittingthe database data to the data storage unit 142 by attaching the itemnumber to each item when the database data is received, but the mannerof manipulating the data at this data receiving unit 141 is alsooptional.

[0172] The data storage unit 142 has been described as storing thedatabase data from the data receiving unit 141 in correspondence to theitem number, but the index to be assigned in units of the data units isalso optional, and can be the page number rather than the item number.Also, instead of producing the data structure according to the itemnumbers and transmitting it to the data control unit 149 at the datadata storage unit 142, a separate unit for producing the data structuremay be provided independently.

[0173] The data deciphering unit 143 has been described as decipheringthe data by using the key in a case the key data is supplied from thedata receiving unit 141, but the data deciphering unit 143 may receivethe enciphering scheme from the data receiving unit 141 instead. Also,it has been described such that the data are outputted as it is whenthere is no received key data, but the basic deciphering scheme may bespecified in advance and the deciphering according to such a basicdeciphering scheme may be applied as a preliminary processing to all thedata.

[0174] The data content of the common book data stored in the commonbook data storage unit 144 is also optional, and a plurality of commonbook data of different types may be provided. It is also possible tochange the style or the size of the characters, or the layout withineach page data at a time of allocating the data content of each itemfrom the data deciphering unit 143 to the data content display portionof the common book data at the book data composition unit 145.

[0175] The input device to be provided on the data operation unit 147 isalso optional and not necessarily limited to the keyboard as describedabove, and the mouse can be used for example. Also, the retrieval schemesuch as the character string retrieval may also be provided as the dataretrieval operation. The manner of specifying the item to the decipheredand displayed is also optional, and the scheme for specifying a desiredentry on the list by the mouse may be employed. Here, a plurality ofitems may be specified at once as the items to be deciphered anddisplayed. In addition, the manner of recognizing the user is optionaland not necessarily limited to the entering of the user registrationnumber from the keyboard at a time of the system activation as describedabove, and the individual ID card may be utilized for this purpose.

[0176] The rules for converting the input signals and the data controlcommands at the input control unit 148 are also optional, and notnecessarily limited to the cases of “→” and “←” which are converted intothe next page and previous page commands as described above.

[0177] The data control unit 149 has been described as memorizing theitem number of the currently displaying data and the data structurereceived from the data storage unit 142, but any index capable ofdistinguishing the data such as the page data may be used instead of theitem numbers. It is also possible to memorizes the item numbersdisplayed in the past. The item number of the data to be initiallydisplayed which is to be memorized is also optional.

[0178] The display request transmission unit 150 has been described asmemorizing the user registration number in advance, and transmitting theitem number and the user registration number to the data center sidesystem 130 whenever the item number is received, but the user identifiersuch as the user registration number may be transmitted at thebeginning.

[0179] As described, according to this second embodiment of FIG. 13, thecharging processing is carried out at the data center side in responseto the request from the user, and the key for deciphering the enciphereddata has been transmitted to the user terminal side from the data centerside, and the deciphering is made at the user terminal side.Consequently, without transmitting the same data twice, the accuratecharging processing can be made at the data center side while making thedeciphering processing at the user terminal side.

[0180] Next, a modification of the above described book data servicesystem of FIG. 13 will be described in detail. In this case, the bookdata service system has a detailed configuration as shown in FIG. 23,which realizes the charging processing according to the databaseutilization and management scheme according to the present invention. Inthis system, there are more than one user terminals even though only oneuser terminal is shown in FIG. 23, and each user terminal side system240 is identified by a user registration number.

[0181] The system of FIG. 23 generally comprises a data center sidesystem 230 and a user terminal side system 240, which are mutuallyconnected through communication line 251.

[0182] The data center side system 230 comprises: a data base datastorage unit 231 for storing a plurality of database data which areidentified by the database numbers; a data enciphering unit 232 forenciphering the database data stored in the database data storage unit231 by using the keys transmitted from the key storage unit 233 whichmemorizes the enciphering algorithm in advance; a key storage unit 233for storing a key corresponding to each database data specified inadvance; a data transmission unit 234 for transmitting the enciphereddatabase data and key data to the user terminal side system 240; a keyrequest input unit 235 for entering the user registration number and thedatabase number as the key registration data; a key retrieval unit 236for retrieving the key data from the key storage unit 233 andtransmitting it to the data transmission unit 234, while also generatinga processing signal for a charging processing; a charging processingunit 237 for carrying out the charging processing in response to theprocessing signal from the key retrieval unit 236; and an individualutilization data management unit 238 for storing database utilizationcharge n correspondence to each user registration number.

[0183] Here, the data transmission unit 234 transmits the database dataenciphered at the data enciphering unit 232 and the database number andthe key data transmitted from the key retrieval unit 236 to the userterminal side system 240 of the specified user registration numberthrough the communication line 251. The key retrieval unit 236 reads outthe key data corresponding to the database number received from the keyrequest input unit 235 out of the key storage unit 233, and transmitsthe user registration number and the database number to the chargingprocessing unit 237, while transmitting the read out key data along withthe received database number and the user registration number to thedata transmission unit 234. The charging processing unit 237 memorizes atable of utilization charge of each database, reads out the utilizationdata of each user from the individual utilization data management unit238 when the user registration number and the database number arereceived from the key retrieval unit 236, carries out the chargingprocessing using the memorized utilization charge table, and, and storesthe obtained new utilization data for this user into the individualutilization data management unit 238.

[0184] On the other hand, the user terminal side system 240 comprises: adata receiving unit 241 for receiving the database data and the key datatransmitted from the data center side system 230; a data storage unit242 for storing the received database data along with the databasenumber; a data deciphering unit 243 for deciphering the database datastored in the data storage unit 242 by using the received key data; acommon book data storage unit 244 for storing common book dataindicating data common to all the book data such as the format data; abook data composition unit 245 for obtaining the book data by composingthe deciphered database data and the common book data; a book datadisplay unit 246 for displaying the composed book data on a display; adata operation input unit 247 for entering the database number specifiedby the data retrieval operation by the user; an input control unit 248for converting the signals entered at the data operation input unit 247and transmitting the converted signals to a data control unit 249 to bedescribed below; and a data control unit 249 for controlling the datastorage unit 242 according to the entered data retrieval operation.

[0185] Here, each database data is attached with the page number, andwhen the database number and the page number are transmitted from thedata control unit 249, the data storage unit 242 transmits the databasedata of the corresponding page number to the book data composition unit245. The data deciphering unit 243 memorizes the deciphering algorithmand the key data transmitted from the data receiving unit 241, deciphersthe database data corresponding to the database number for which the keydata is memorized when the database data is received from the datareceiving unit 241, and transmits the deciphered database data to thedata storage unit 242. The book data composition unit 245 produces thebook data by allocating the data content received from the data storageunit 242 to the data content display portion of the common book datastored in the common book data storage unit 244.

[0186] The data control input unit 247 is equipped with an input devicesuch as a keyboard for example, and the operation for specifying thedisplay of the next page or the previous page for example is carried outas the data retrieval operation. The operation for specifying thedisplay of the next page or the previous page can be made by pressing“→” key or “←” key for example. The input control unit 248 transmits thecommands for the next page or the previous page to the data control unit249 when the entered signal is “→” or “←”. The data control unit 249memorizes the currently displaying database number and page number, andupdates the memorized page number to the page number greater by one whenthe next page command is received, or to the page number smaller by onewhen the previous page command is received, and transmits the memorizedpage number to the data storage unit 242.

[0187] Now, the operation in this modified embodiment of FIG. 23 iscarried out according to the flow chart of FIG. 24 as follows.

[0188] When the request for transmitting the key is entered at the keyrequest input unit 235 of the data center side system 230, the keyretrieval unit reads out the corresponding key from the key storage unit233. Then, the charging processing unit 237 carries out the chargingprocessing by updating the utilization data in the individualutilization data management unit 238 (step S151), and the key data istransmitted from the data transmission unit 234 to the user terminalside system 240 (step S152). The key data received at the data receivingunit 241 of the user terminal side system 240 is then memorized in thedata deciphering unit 243.

[0189] On the other hand, the database data stored in the database datastorage unit 231 is enciphered by the corresponding key read out fromthe key storage unit 233 at the data enciphering unit 232 (step S153).The enciphered database data is then transmitted from the datatransmission unit 243 to the data receiving unit 241 of the userterminal side system 240 (step S154), and deciphered by using the keydata memorized in the data deciphering unit 243 (step S155). and thenstored in the data storage unit 242.

[0190] Here, the user can execute the data retrieval operation from thedata operation input unit 247. The data retrieval operation entered atthe data operation input unit 247 is then converted at the input controlunit 248, and transmitted to the data control unit 249. The data controlunit 249 calculates the page number of the data to be displayed, andtransmits it to the data storage unit 242, in response to which the datastorage unit 242 reads out and transmits the corresponding database datato the book data composition unit 245. Then, the book data compositionunit 245 produces the book data by composing the transmitted databasedata with the common book data stored in the common book data storageunit 244, and the obtained book data is displayed at the book datadisplay unit 246 (step S156).

[0191] Next, the further detailed concrete examples concerning theembodiment of FIG. 23 will be described.

[0192] The database data storage unit 231 on the data center side system230 stores ten database data A to J, and a case of making an access tothe database data E will be described. Here, it is assumed that the userregistration number corresponding to the user terminal side system 240is “A1234”, and the database utilization charge of “3000” is alreadymemorized in the individual utilization data management unit 238 forthis user registration number.

[0193] In this case, the key storage unit 233 stores the correspondencetable of the database data and the keys as shown in FIG. 25, incorrespondence to the ten database data A to J, while the chargingprocessing unit 237 memorizes the utilization charge table as shown inFIG. 26 for the ten database data A to J.

[0194] First, the key request input unit 235 enters the userregistration number “A1234” and the database number “E” as the keyrequest data, which is transmitted to the key retrieval unit 236. Thekey retrieval unit 236 then reads out the key “2” corresponding to thedatabase number “E” according to the correspondence table of FIG. 25stored in the key storage unit 233. Then, the key retrieval unit 236transmits the user registration number “A1234” to the chargingprocessing unit 237, and then transmits the user registration number“A1234”, the database number “E”, and the key “2” to the datatransmission unit 234. The charging processing unit 237 reads out thedatabase utilization charge of “3000” of this user from the individualutilization data management unit 238 according to the received userregistration number “A1234”, adds the utilization charge of “2500” forthe database “E” to this database utilization charge, and stores the newvalue of “5500” as the database utilization charge of the user “A1234”in the individual utilization data management unit 238. Then, when theuser registration number “A1234”, the database number “E”, and the key“2” are received, the data transmission unit 234 transmits the receiveddatabase number and the key to the data receiving unit 241 of the userterminal side system 240 for the user with the user registration number“A1234”.

[0195] The data receiving unit 241 of the user terminal side system 240then receives the transmitted database number “E” and the key “2”through the communication line 251, and transmits them to the datadeciphering unit 243, which then memorizes these database number “E” andkey “2”.

[0196] On the other hand, the database data storage unit 231 of the datacenter side system 230 transmits the stored ten database data A to J tothe data enciphering unit 232. The data enciphering unit 232 then readsout the keys corresponding to these database numbers stored in the keystorage unit 233 according to the correspondence table shown in FIG. 25,enciphers each database data A to J by the enciphering algorithmmemorized in advance by using the corresponding key, and transmits theenciphered database data to the data transmission unit 234. The datatransmission unit 234 then transmits the enciphered database data to thedata receiving unit 241 of the user terminal side system 240 through thecommunication line 251.

[0197] The receiving unit 241 which received the enciphered databasedata from the data center side system 230 then transmits the receiveddatabase data to the data deciphering unit 243, which deciphers thosereceived database data whose corresponding keys are memorized, such asthe database data “E” for which the key “2” has been memorized,according to the deciphering algorithm memorized in advance., andtransmits all the database data to the data storage unit 242. The datastorage unit 242 then stores the transmitted ten database data.

[0198] Then, the data control unit 249 transmits the database number “E”and the page number “1” to the data storage unit 242 as the data to beinitially displayed. In response, the data storage unit 242 reads outand transmits the data content of the first page of the database data“E” to the book data composition unit 245, which produces the book dataaccordingly. At this point, the data content of the first page of thedatabase data “E” is given in a form of the above described FIG. 17,while the data content of the second page is also given in a form of theabove described FIG. 21. Then, the book data composition unit 245produces the book data by allocating the data content as in FIG. 17received from the data storage unit 242 to the data content displayportion of the common book data as in FIG. 19 stored in the common bookdata storage unit 244, and transmits the obtained book data to the bookdata display unit 246, which then displays the received book data as inthe above described FIG. 20 on its display.

[0199] Here, when the key “→” is pressed as the data retrieval operationat the data operation input unit 247, the input signal is transmitted tothe input control unit 248, which converts this input signal into thenext page command and transmits the converted command to the datacontrol unit 249. The data control unit 249 which received this nextpage command then rewrites the currently displaying page number from “1”to “2”, and transmits the database number “E” and the page number “2” tothe data storage unit 242. In response, the data storage unit 242transmits the data content of the second page of the database data “E”as shown in the above described FIG. 21 to the book data compositionunit 245. Then, the book data composition unit 245 produces the bookdata by allocating the data content as in FIG. 21 received from the datastorage unit 242 to the data content display portion of the common bookdata as in FIG. 19 stored in the common book data storage unit 244, andtransmits the obtained book data to the book data display unit 246,which then displays the received book data as in the above describedFIG. 22 on its display.

[0200] In the modified embodiment of FIG. 23 described above, variousmodifications are possible as follows.

[0201] In the above, a case of storing ten database data has beendescribed, but the number of database data to be stored is optional. Itis also possible to control the transmission of the database data suchthat only the database data of the database number for which the keyrequest is made is going to be transmitted. It is also possible for thedatabase to be distributed at a plurality of locations and the accessesto the distributed database can be made through the communication lines.Also, the content, the format, or the data structure of the databasedata are optional. Also, the enciphering algorithm is optional, and maybe changed depending on the database data.

[0202] The key storage unit 233 has been described as storing the key incorrespondence to the database data, but the correspondence of the keymay not necessarily be made in units of database data, and the same keymay be shared by a plurality of database data. It is also possible tostore the enciphering scheme instead of the key.

[0203] The data transmission scheme and the communication medium fromthe data center side system 230 to the user terminal side system 240 arealso optional, and can be the satellite communication, or thesimultaneous broadcasting to a plurality of the user terminal sidesystem 240.

[0204] The key request input unit 235 has been described as entering thedatabase number as the key request data, but there may be a plurality ofkey request data.

[0205] The input device to be provided on the data operation unit 235 isalso optional and can be the mouse, or the remote input device using thecommunication line. In addition, the manner of recognizing the user isoptional and not necessarily limited to the entering of the userregistration number as described above, and the individual ID card maybe utilized for this purpose.

[0206] The content to be received and transmitted at the key retrievalunit 236 depends on the content entered from the key request input unit235 and the content stored in the key storage unit 233. Also, instead oftransmitting the key data to the data transmission unit 234, the keydata may also be transmitted to the data enciphering unit 232 such thatthe key data are also enciphered and then transmitted.

[0207] The utilization charge of the database data may be setoptionally, and can be different for different database data as in theabove, or can be uniform for all the database data. This chargingprocessing may also be carried out on the other system terminalconnected through the communication network, and the individualutilization data management unit 138 may also be provided on the othersystem terminal connected through the communication network.

[0208] The data storage unit 242 has been described as storing thedatabase number along with the database data and each database data hasbeen described as attached with the page number, but the data unitsbased on the data structure may be used instead of the page numbers.

[0209] The data content of the common book data stored in the commonbook data storage unit 244 is also optional, and a plurality of commonbook data of different types may be provided. It is also possible tochange the style or the size of the characters, or the layout withineach page data at a time of allocating the data content of each itemfrom the data deciphering unit 243 to the data content display portionof the common book data at the book data composition unit 245.

[0210] The input device and the procedure of the data retrievaloperation in the data operation unit unit 247 are also optional and notnecessarily limited to the pressing of the keys on the keyboard asdescribed above, and the mouse can be used for example. Also, theretrieval scheme such as the character string retrieval may also beprovided as the data retrieval operation. The conversion rules forconverting the input signals into the commands at the input control unit248 are also optional.

[0211] The data control unit 249 has been described as memorizing thecurrently displaying database number and page number, but it is notnecessarily limited to the page number, and the other index capable ofdistinguishing the data such as the item number may be used instead. Itis also possible to memorizes the page numbers displayed in the past.The page number of the data to be initially displayed which is to bememorized is also optional.

[0212] As described, according to this modified embodiment of FIG. 23,the charging processing is carried out as the key for deciphering thespecified database data is transmitted from the data center side system230 to the user terminal side system 240, and the corresponding databasedata transmitted to the user terminal side system 240 is deciphered atthe user terminal side system 240. Consequently, without transmittingthe same data twice, the accurate charging processing can be made at thedata center side while making the deciphering processing at the userterminal side.

[0213] As described, according to this second embodiment, the chargingprocessing is carried out at the data center side and the key fordeciphering the requested data content is transmitted to the userterminal side from the data center side, and the deciphering is made atthe user terminal side, so that the accurate charging processing can bemade without transmitting the same data twice. As a result, the safecommunication of the data can be achieved without increasing the amountof communication, while the accurate management of the databaseutilization state can be realized. In addition, as the spread one pagein the book data is used as the data unit, the operation scheme and thedata structure are easily comprehensible, and the retrieval by turningpages one by one is also possible, so that the easy handling of thesystem can be improved.

[0214] Next, the third embodiment of the book data service systemaccording to the present invention will be described in detail.

[0215] In this third embodiment, the book data service system has asystem configuration as shown in FIG. 27 where, the system configurationof FIG. 11 for the second embodiment described above is modified in thatthe computer 51B of the data center 50B has a remote record inspectionunit 272 which replaces the deciphering key returning unit 113 in FIG.11, while the user terminal 55B has a deciphering communication device271 which replaces the communication device 112B in FIG. 11.

[0216] The user terminal 55B has a detailed configuration as shown inFIG. 28 where the configuration of FIG. 12 for the second embodimentdescribed is modified in that the computer 56B includes a decipheringrequest unit 287 connected between the book data display unit 63A andthe deciphering communication device 271, while the decipheringcommunication device 271 includes a communication unit 281, adeciphering unit 282, and a control unit 283, where the a control unit283 further comprises a buffer 284 for temporarily storing data to bedeciphered or the deciphered data, a utilization record unit 285 forrecording the utilization record of the book data service, and a remoteinspection response unit 286 for returning the utilization recordrecorded by the utilization record unit 285 in response to the remoterecord inspection from the data center 50B.

[0217] This system shown in FIG. 27 and FIG. 28 operates similarly as inthe second embodiment described above up until the request from the useris received by the book data display unit 63A, but the scheme fordeciphering the book data and the scheme for charging the user aredifferent as follows.

[0218] In this third embodiment, when the deciphering of the book datais requested by the user, the request is given to the decipheringrequest unit 287 from the book data display unit 63A, and thedeciphering request unit 287 transmits the enciphered book data to thedeciphering communication unit 271 by dividing the entire book data inappropriate units such as units of pages. The deciphering communicationunit 271 receives the enciphered book data transmitted from thedeciphering request unit 287 at the control unit 283, stores thereceived book data temporarily in the buffer 284, and transmits thetemporarily stored book data sequentially to the deciphering unit 282.Then, the deciphered book data obtained by the deciphering unit 282 isreturned to the control unit 283, stored temporarily in the buffer 284,and returned to the deciphering request unit 287.

[0219] At a time of returning the deciphered book data to thedeciphering request unit 287, the book code, page number, and chapternumber of the deciphered book data as well as the date and time ofdeciphering are reported to the utilization record unit 285 and recordedtherein. Here, the detailed record described above is recorded in orderto present the detailed account at a time of the claiming the payment,but it is possible to adopt the simpler scheme of adding up thepredetermined utilization charges sequentially at every occasion ofutilizing the book data service. When the deciphered book data isreturned to the deciphering request unit 287, the buffer 284 of thecontrol unit 283 is released. Whether or not to store the decipheredbook data is similarly handled as in the second embodiment describedabove.

[0220] The remote record inspection unit 272 of the data center 50Bcalls up the deciphering communication unit 271 of each user terminal55B at an appropriate interval such as one month, and requests thetransfer of the utilization record. Then, in the decipheringcommunication unit 271, the request from the data center 50B istransmitted through the communication unit 281 to the control unit 283,and the utilization record is read out from the utilization record unit285 and the transfer data is constructed at the remote inspectionresponse unit 286, and returned to the remote record inspection unit 272through the communication unit 281. When the returning of the transferdata is completed, the utilization record in the utilization record unit285 is cleared. The remote record inspection unit 272 then transmits thereceived transfer data to the charging unit 114 which applies thecharging processing to the transfer data.

[0221] In this third embodiment, the high level security of theutilization record content is required, so that the decipheringcommunication device 271 should be provided by the data center sideservice provider or by the third party approved by the data center sideservice provider, and when the user terminal side does not respond tothe utilization record remote inspection from the data center, themeasure to remove the deciphering communication device 271 can be taken.In addition, it is also possible to encipher the utilization record inorder to prevent the response using the fake communication device.

[0222] In further detail, according to this third embodiment, the bookdata service system has a detailed configuration as shown in FIG. 29,which generally comprises a data center 290 and a user terminal 300. Thedata center 290 includes a book data storage unit 291, an encipheringunit 292, and a book data broadcasting unit 293. Here, the book datastorage unit 291 stores the book data as well as the book frame data,while the enciphering unit 292 enciphers the book data received from thebook data storage unit 291 and the book data broadcasting unit 293broadcasts the enciphered book data to the user terminal 300 connectedwith this data center 290.

[0223] The user terminal 300 includes a book data receiving unit 301, abook data storage unit 302, a book data selection unit 303, a book datatemporal storage unit 304, a book data display unit 305, and adeciphering unit 310. The book data receiving unit 301 receives theenciphered book data from the data center 290, while the book datastorage unit 302 stores the received book data. The book data selectionunit 303 allows the user to select the desired book data to bedeciphered, while the book data temporal storage unit 304 temporarilystores the deciphered book data. The book data display unit 305 displaysthe deciphered book data, while the deciphering unit 310 deciphers theenciphered book data selected at the book data selection unit 303.

[0224] Here, the deciphering unit 310 includes a deciphering device 311,a measurement unit 312, a utilization level meter 313, and a meterindication unit 314. The deciphering device 311 deciphers the encipheredbook data, while the measurement unit 312 measures the utilization levelby adding up such quantities as a time in use for the deciphering device311, or an amount of deciphered data, or a number of deciphered caseswhenever the deciphering device 311 is used. The utilization level meter313 records the utilization level measured by the measurement unit 312,while the meter indication unit 314 indicates the utilization levelrecorded by the utilization level meter 313.

[0225]FIG. 30 shows an exemplary data recorded by the utilization levelmeter 313 including the time in use, the amount of deciphered data, andthe number of deciphered cases.

[0226]FIG. 31 shows an exemplary display for the book data selectionunit 303 in which the user has selected the desired book data to bedeciphered, which is the comic book called “comics XX” in an exemplarycase shown in FIG. 31 as indicated by the shading.

[0227]FIG. 32 shows an exemplary display of the book data at the bookdata display unit 305 for the book data selected in FIG. 31, whichcomprises a number of comic frames 321, while the display alsoincorporates a previous page button 322 and a next page button 323.

[0228] Now, for an exemplary case of using the display for the book dataselection unit 303 as shown in FIG. 31, the display of the book datadisplay unit 305 as shown in FIG. 32, and the indication of the meterindication unit 314 as shown in FIG. 30, this third embodiment operatesas follows.

[0229] First, the book data stored in the book data storage unit 291 ofthe data center 290 is supplied to the enciphering unit 292 whichenciphers the supplied book data. The enciphered book data is thensupplied to the book data broadcasting unit 293 which broadcasts thesupplied book data.

[0230] Then, the broadcasted book data is received by the book datareceiving unit 301 of the user terminal 300, and stores in the book datastorage unit 302. At this point, the user selects the desired book datato be deciphered by using the book data selection unit 303. The selectedbook data is then supplied to the deciphering device 311 of thedeciphering unit 310 which deciphers the selected book data. Then, thedeciphered book data is temporarily stored in the book data temporalstorage unit 304, and displayed at the book data display unit 305.

[0231] Next, the deciphered book data is given to the measurement unit312, and the time in use of the enciphering device 311, or the amount ofdeciphered data, or the number of deciphered cases is measured by themeasurement unit 312, and the measured value is recorded as theutilization level by the utilization level meter 313, while the meterindication unit 314 indicates the utilization level recorded by theutilization level meter 313.

[0232] It is to be noted that the third embodiment described above canbe modified variously as follows. For example, the meter indication unit314 may be made to indicate the utilization level only when the userrequests. Also, a number of the user terminals to be included in thesystem is optional. Also, the content of the book data to be stored inthe book data storage unit 291 of the data center 290 are notnecessarily limited to those shown in FIG. 31 such as the comics,magazines, job information, the housing information, and newspaper, andoptional. Also, the number of types of the book data stored in the bookdata storage unit 291 of the data center 290 is not limited to five asin the example described above, and optional so that it may be one orone hundred. Also, in a case of classifying the data content of the bookdata stored in the book data storage unit 291 of the data center 290, anumber of classes or the hierarchical structures used in theclassification are optional. Also, a number of books registered in thedata center 290 is optional, while the color, shape, layout,ornamentation, thickness, and size of each book data are also optional.

[0233]FIG. 33 shows a modified configuration for the third embodimentdescribed above, which differs from the configuration of FIG. 29 in thatthe deciphering unit 310 further includes a utilized book code memoryunit 315 connected with the deciphering unit 311 and the measurementunit 312, which stores the book codes of the book data deciphered andutilized by the user. The rest of this configuration of FIG. 33 issubstantially equivalent to that of FIG. 29.

[0234]FIG. 34 shows an exemplary data recorded by the utilization levelmeter 313 in this modified configuration, including the utilized bookcodes along with the time in use, the amount of deciphered data, and thenumber of deciphered cases.

[0235] Now, for an exemplary case of using the display for the book dataselection unit 303 as shown in FIG. 31, the display of the book datadisplay unit 305 as shown in FIG. 32, and the indication of the meterindication unit 314 as shown in FIG. 34, this modified configuration ofFIG. 33 operates as follows.

[0236] First, the enciphered book data broadcasted from the data center290 as in the configuration of FIG. 29 is received at the book datareceiving unit 301 of the user terminal 300, and deciphered by thedeciphering device 311, while the deciphered book data is temporarilystored in the book data temporal storage unit 304 and displayed by thebook data display unit 305 as in the configuration of FIG. 29.

[0237] Then, the deciphered book data are given to the utilized bookcode memory unit 315 and the book codes of the deciphered book data arememorized by the utilized book code memory unit 315. The memorized bookcodes are then supplied to the measurement unit 312 along with thedeciphered book data supplied from the deciphering device 311. Here, themeasurement unit 312 does not measure the utilization level when thebook code of the deciphered book data supplied from the decipheringdevice 311 coincides with any of the book codes memorized in theutilized book code memory unit 315. Thereafter the operation similar tothat in the configuration of FIG. 29 is carried out.

[0238] Thus, in this modified configuration of FIG. 33, the book codesmemorized in the utilized book code memory unit 315 are used to indicatethose book data which had been deciphered before, such that there-deciphering of such once deciphered book data by the decipheringdevice 310 is not going to be charged, as the utilization level is leftunchanged.

[0239]FIG. 35 shows another modified configuration for the thirdembodiment described above, which differs from the configuration of FIG.29 in that the deciphering unit 310 further includes a transmission unit316 connected with the utilization level meter 313, which transmits theutilization level data such as the time in use of the deciphering device311, the amount of deciphered data, or the number of deciphered cases toa charging center 320 connected to the user terminal 300.

[0240] Here, the charging center 320 includes a reception unit 321, acharge calculation unit 322, and a charge memory unit 323. The receptionunit 321 receives the utilization level data transmitted from thetransmission unit 316 of the user terminal 300 connected to the chargingcenter 320. The charge calculation unit 322 receives the utilizationlevel data received by the reception unit 321 and calculates the chargesaccording to the utilization level data. The charge memory unit 323memorizes the charges calculated by the charge calculation unit 322. Therest of this configuration of FIG. 35 is substantially equivalent tothat of FIG. 29.

[0241] Now, this modified configuration of FIG. 35 operates as follows.

[0242] In this case, the operation up until the book data is displayedby the book data display unit 305 and the operation up until theutilization level recorded by the utilization level meter 313 isindicated by the meter indication unit 314 are substantially similar tothose in FIG. 29. The utilization level meter 313 transmits the recordedutilization level data to the transmission unit 316 at appropriatetiming such as at the constant interval or when the utilization levelexceeds a predetermined level. Then, the transmission unit 316 calls upthe charging center 320 to set up the communication path, and transmitsthe utilization level data to the charging center 320.

[0243] At the charging center 320, the utilization level datatransmitted from the transmission unit 316 of the user terminal 310 isreceived by the reception unit 321, and the charges are calculated bythe charge calculation unit 322 according to the received utilizationlevel data, and memorized by the charge memory unit 323.

[0244] It is to be noted that the modified configuration of FIG. 35described above can be further modified variously as follows. Forexample, the transmission and reception of the utilization level datahas been described as called up from the user terminal side, but thiscan be modified such that the charging center 320 calls up the userterminal 300 at appropriate timing to request the transmission of theutilization level data, and in response, the transmission unit 316transmits the utilization level data recorded by the utilization levelmeter 313. Also, the transmission unit 316 has been described asincluded in the deciphering unit 310, but it may be contained in themain body of the computer constituting the user terminal 300. Also, anumber of user terminal connected to the charging center is not limitedto one as described above, and optional. Also, the charging center 320has been described as being provided outside of the data center 290, butthe charging center 320 may be incorporated within the data center 290.Also, the charging center 320 having the utilization level datamanagement function as described above may be utilized for the purposeother than the charging.

[0245]FIG. 36 shows still another modified configuration for the thirdembodiment described above, which differs from the configuration of FIG.29 in that a part of the book data stored in the book data storage unit291 is directly given to the book data broadcasting unit 293 in theunenciphered state by bypassing the enciphering unit 292 in the datacenter 290 side, while the unenciphered book data received by the bookdata receiving unit 301 is directly given to the book data display unit305 by bypassing the book data storage unit 302, the deciphering unit310, and the book data temporal storage unit 304 in the user terminal300 side. The rest of this configuration of FIG. 36 is substantiallyequivalent to that of FIG. 29.

[0246] Now, this modified configuration of FIG. 36 operates as follows.

[0247] First, a part of the book data stored in the book data storageunit 291 is directly given to the book data broadcasting unit 293 in theunenciphered state while the remaining part of the book data stored inthe book data storage unit 291 is given to the enciphering unit 292 andenciphered therein, such that the enciphered book data is given to thebook data broadcasting unit 293. Then, the book data in the unencipheredstate as well as the enciphered book data are broadcasted from the bookdata broadcasting unit 293 and received by the book data receiving unit301 of the user terminal 300.

[0248] Then, the unenciphered book data received by the book datareceiving unit 301 is directly given to the book data display unit 305and displayed thereon, while the enciphered book data are handledsimilarly as in the configuration of FIG. 29 up until the book data isdisplayed on the book data display unit 305 and the utilization leveldata recorded by the utilization level meter 313 is indicated by themeter indication unit 314.

[0249] As described according to this third embodiment, the encipheredbook data are received and stored at the user terminal, and the bookdata selected from the stored book data are deciphered and displayed,while the utilization level data such as the time in use of thedeciphering device, the amount of deciphered data, or the number ofdeciphered cases are measured, recorded, and indicated, so that the datautilization time and the data utilization amount of all the users can bemeasured accurately. Consequently, by utilizing this utilization leveldata for the charging, the accurate utilization charges can be chargedto all the users. It is also possible to utilize this utilization leveldata for the other purpose such as the check of the access frequency ofa given book for instance.

[0250] Next, the fourth embodiment of the book data service systemaccording to the present invention will be described in detail.

[0251] In this fourth embodiment, the book data service system has asystem configuration similar to that shown in FIG. 5 for the firstembodiment described above. In this case, however, as shown in FIG. 37,the computer 56C of the user terminal includes the book data managementunit 62C having a storage reservation unit 371 for reserving the storageof the book data, and the book data storage unit 61C having a broadcastschedule storage unit 372 for taking out the broadcast schedule tablefrom the received book data, and a book reservation inspection unit 373for checking whether the book data other than the broadcast schedule hasbeen reserved or not. The rest of the user terminal in this fourthembodiment is substantially equivalent to that of FIG. 6 for the firstembodiment described above.

[0252] It is to be noted that the above features of this fourthembodiment are totally unrelated with the characteristic features of thesecond and third embodiments concerning the deciphering function and thecharging function, so that this fourth embodiment can be combined witheither one or both of the second and third embodiments described above.

[0253] In this fourth embodiment, the basic feature is that the bookcodes of the book data to be stored are memorized, and the book datareceived from the broadcasting is stored only when the book code of thebroadcasted book data coincides with any one of the memorized bookcodes.

[0254] Here, the reservation of the book code can be made by activatingthe book data management unit 62C to display a book menu, from which thebroadcast schedule table can be selected to display the broadcastschedule table by the book data display unit 63, where this broadcastschedule table is to be regularly distributed and updated. The displayof the broadcast schedule table is made in a form of a list as shown inFIG. 38, in which the data concerning the book title, the publisher'sname, the author, the field of the subject matter, etc. are enlistedover a plurality of pages, from which the desired books can be selectedby specifying the lines of the desired books by the mouse, or setting acursor on the lines of the desired books and pressing the return key onthe keyboard, for example. The book codes of the selected books are thenstored in the reservation table provided in a memory of the computer56C. Here, the selection can be made easier by broadcasting the books ofthe same field consecutively and providing appropriate headers in thebroadcast schedule table.

[0255] In a case the main power of the user terminal is to be normallyturned off in view of the power saving, the time zone at which the bookdata are scheduled to be broadcasted is registered into a timermanagement function for operating the user terminal with the minimumpossible power while providing ample margins before and after the bookdata at the same time the book code is registered. This timer managementfunction turns on the main power of the broadcast receiver 57 and thecomputer 56C automatically when the reserved time arrives, and controlsthe computer 56C to activate the book data storing functionautomatically. This timer management unit can be realized by theextension of the timer function of the computer 56C, or may be providedas a separate hardware in a case of using the general purpose computer.Also, the reservation codes are stored in the hard disk device, and readout after the activation of the book data storing function. Thebroadcast schedule table is to be delivered at the predetermined time sothat it can be received without requiring the user to make a reservationfor the broadcast schedule table itself.

[0256] In this fourth embodiment, the storing of the book data iscarried out according to the flow chart of FIG. 39 as follows.

[0257] When the broadcast receiver 57 receives the book data, the errorcorrected data are transmitted to the computer 56C (step S201). Then,the computer 56C searches the book code of the received data at the bookdata storage unit 61C, and in a case the book code cannot be found, thebroadcast schedule storage unit 372 of the book data storage unit 61Cchecks if it is the broadcast schedule table or not (step S202). If so,the broadcast schedule storing processing is carried out by thebroadcast schedule storage unit 372 (step S203). Otherwise, the bookreservation inspection unit 373 of the book data storage unit 61C checkswhether the book code of the received data is the reserved book code ornot (step S204). If not, the received data is ignored and the nextreceived data Is awaited, whereas otherwise, whether there is anyreception error or not is checked (step S205). When there is noreception error, the received data is stored in the file memory (stepS206), and registered in the management table provided in the book datamanagement unit 62C as the already stored book (step S207), while thereservation code is deleted from the reservation table (step S208).

[0258] When there is a reception error at the step S205, next whetherany partially stored data for this book data exists or not is inquiredto the book data management unit 62C (step S209), and if there is somepartially stored data, the error portion of the old data is replaced bythe correct portion of the new data (step S210). To this end, the bookdata is divided into appropriate blocks, and stored such that thereplacement of the error portion can be made in units of the blocks. Forexample, the block can be formed in units of pages. Then, whether thedata obtained by the replacement at the step S210 is the complete dataor not is judged (step S211). If so, the steps S206 to S208 describedabove are carried out for this complete data.

[0259] When there is no partially stored data at the step S209, or whenthe data obtained by the step S210 is not the complete data, whether thenext broadcast of this book data is scheduled or not is judged (stepS212). If the next broadcast scheduled, the received data with theerrors is partially stored in the file memory with indications of theerrors (step S213) and registered in the partially storage managementtable provided in the book data management unit 62C (step S214), whereasotherwise the received data is discarded and the reservation code isdeleted from the reservation table (step S215). Here, the deletion ofthe reservation code is necessary in order to avoid the redundantstorage at a time of the re-broadcasting.

[0260] Also, in this fourth embodiment, the storing of the broadcastschedule table is carried out according to the flow chart of FIG. 40 asfollows.

[0261] The broadcast schedule table is assigned with a serial number,and whether the received broadcast schedule table is the re-broadcastingof the already stored broadcast schedule table or not is judged bychecking the serial number of the received broadcast schedule table tothe book data management unit 62C (step S301). If it is the alreadystored broadcast schedule table, the operation is terminated withoutstoring the received broadcast schedule table. Otherwise, whether thereis any reception error or not is checked (step S302). If not, thereceived broadcast schedule table is stored in the file memory (stepS303) and registered in the management table provided in the book datamanagement unit 62C (step S304).

[0262] When there is a reception error at the step S302, next whetherany partially stored data for this broadcast schedule table exists ornot is inquired to the book data management unit 62C (step S305), and ifthere is some partially stored data, the error portion of the old datais replaced by the correct portion of the new data (step S306). Then,whether the data obtained by the replacement at the step S306 is thecomplete data or not is judged (step S307). If so, the steps S303 andS304 described above are carried out for this complete data.

[0263] When there is no partially stored data at the step S305, or whenthe data obtained by the step S306 is not the complete data, thereceived broadcast schedule table with the errors is partially stored inthe file memory with indications of the errors (step S308) andregistered in the partially storage management table provided in thebook data management unit 62C (step S309).

[0264] Here, the serial number of the broadcast schedule table is to besufficiently many cyclic numbers such that there is only sufficientlylittle possibility for the serial number to come once around as thereception errors of the broadcast schedule table occurs recurrently.

[0265] In a case of normally turning off the main power and limiting thetime zone for the broadcast reception, the the main power is turned onautomatically and the book data storage unit 61C is activated by theoperation of the timer management function when the reserved startingtime arrives, and the system is de-activated and the main power isturned off automatically when the ending time arrives, but other thanthat, the operation at a time of receiving the book data broadcasting issimilar to the case of not using the time zone limitation. Here,however, it is necessary to make the reservation of the time zone againin a case of expecting the re-broadcasting as the received broadcastschedule table was incomplete.

[0266] Alternatively, according to this fourth embodiment, the book dataservice system can have a detailed configuration as shown in FIG. 41,which generally comprises a data center 420 on a data provider 410 sideand a user terminal 430 on a user 440 side. The data center 420 includesa data input unit 421, an advertisement entry code assignment unit 422,a data storage unit 423, and a data transmission unit 424. Here, thedata provider 410 enters the book data and the advertisement entry datawhich briefly describes the content of the book through the data inputunit 421.

[0267] The book data and the advertisement entry data are automaticallyassigned with the book code and the advertisement entry code, while theadvertisement entry data is also assigned with the broadcast stationcode to be described below. The book data with the book code assigned isgiven in a format shown in FIG. 44.

[0268] The advertisement entry code assignment unit 422 assign theadvertisement entry code assigned to the advertisement entry data to thecorresponding book data. The book data with the advertisement entry codeis given in a format shown in FIG. 45.

[0269] The book data with the advertisement entry code assigned and theadvertisement entry data are then stored in the data storage unit 423,and the stored book data and the advertisement entry data arebroadcasted from the data transmission unit 424 according to thebroadcast schedule as shown in FIG. 46. Here, the exemplary broadcastschedule of FIG. 46 shows a case of providing a plurality of broadcaststations (broadcast channels). In other words, either a plurality of thedata centers 420 are provided, or the data transmission unit 424 hasmulti-channel broadcasting function.

[0270] On the other hand, the user terminal 430 includes a datareception unit 431, an advertisement entry code comparison unit 432, abook code matching unit 433, a data storage unit 434, a book data outputunit 435, an advertisement entry selection input unit 436, and anadvertisement entry code memory unit 437.

[0271] The data reception unit 431 receives the broadcast of eachbroadcast station selectively, according to the broadcast station fromwhich the broadcast should be received which is reserved by thebroadcast station code assigned to the advertisement entry data when theadvertisement entry code is entered at the advertisement entry selectioninput unit 436 as described below.

[0272] Namely, the user 440 can make a reservation for the desired bookto be stored by switching to the selection input mode in a state ofdisplaying the advertise entry at the book data output unit 435. Anexemplary display of the advertisement entry is made as shown in FIG.42, which shows an exemplary case in a format in which the advertisemententry data are superposed over the book data within the advertisemententries 441 and 442. When a cursor 443 is set to the desiredadvertisement entry by the advertisement entry selection input unit 436such as the mouse, and the execution key such as the click button of themouse is operated at this position, the storing of the book described bythe selected advertisement entry can be reserved. In FIG. 42, the cursor443 is set on the advertisement entry 442 (as indicated by the shadingin FIG. 42), and the execution key is operated.

[0273] When the advertisement entry 442 is selected, the advertisemententry code memory unit 437 stores the advertisement entry code such as“12345A” for example. Also, according to the broadcast station codeassigned to the advertisement entry data, the reservation of thebroadcast station from which the broadcast should be received by thedata reception unit 431 is made.

[0274] When the advertisement entry code is stored in the advertisemententry code memory unit 437, the corresponding book data is broadcastedfrom the data center 420. Then, when the broadcasted book data isreceived by the data reception unit 431, the advertisement entry codeassigned to the received book data is compared with the advertisemententry code stored in the advertisement entry code memory unit 437 at theadvertisement entry code comparison unit 432.

[0275] As a result of the comparison, when the advertisement entry codescoincide, the book code of the received book data is transmitted to thebook code matching unit 433, and the matching with the book code of thebook data already stored in the data storage unit 434 is made. As aresult of the matching, when no identical book code is present in thedata storage unit 434, the received book data is stored in the datastorage unit 434, whereas otherwise the storing is interrupted.

[0276] An exemplary advertisement entry code stored in the advertisemententry code memory unit 437 is shown in FIG. 43. As shown in FIG. 43, theadvertisement entry code memory unit 437 is capable of storing aplurality of the advertisement entry codes. In a case the book data isstored in the data storage unit 434, the corresponding advertisemententry code is deleted from the advertisement entry code memory unit 437,so as to utilize the memory capacity of the advertisement entry codememory unit 437 efficiently.

[0277] The outline of the program implemented in the advertisement entrycode comparison unit 432 is shown in FIG. 47, in which the receivedadvertisement entry code is set to be Cl (step S471), while the end flagis set initially to zero (step S472). Then, one stored advertisemententry code in the advertisement entry code memory unit 437 is set to beC2 (step S473), and unless it is the data end, whether C1 is equal to C2or not is checked (step S475). If they are equal, the received book datais transmitted to the book code matching unit 433 (step S476), and thenthe end flag is set to 1 (step S477), whereas otherwise the steps S476and S477 are skipped. On the other hand, when it is the data end at thestep S473, the end flag is set to 1 (step S474) and the steps S475 toS477 are skipped. Then, as long as the end flag is not equal to 1, theloop of the steps S473 to S477 is repeated (step S478). When the endflag is equal to 1 at the step S478, the operation of the advertisemententry code comparison unit 432 is terminated.

[0278] The outline of the program implemented in the book code matchingunit 433 is shown in FIG. 48, in which the book code of the receivedbook data is set to be C1 (step S481), while the end flag is setinitially to zero (step S482). Then, one book code read out from thedata storage unit 434 is set to be C2 (step S483), and unless it is thedata end, whether C1 is equal to C2 or not is checked (step S485). Ifthey are not equal, as long as the end flag is not equal to 1, the loopof the steps S483 to S485 is repeated (step S486). On the other hand,when it is the data end at the step S483, the end flag is set to 1 (stepS484) and the step S485 is skipped. When the end flag is equal to 1 atthe step S486, the received book data is stored in the data storage unit434 (step S487), and the corresponding advertisement entry code in theadvertisement entry code memory unit 437 is deleted (step S488). When C1is equal to C2 at the step S485, the steps S486 to S488 are skipped, andthe operation of the book code matching unit 433 is terminated.

[0279] It is to be noted that the advertisement entries 441 and 442 havebeen described as being treated as a part of the book data, but it isalso possible to handle the book data and the advertisement entry dataas separate data. In a case of handling the advertisement entry data,the dedicated memory region for storing the advertisement entry data isprovided in the data storage unit 434, such that the advertisement entrydata is added to this memory region whenever the advertisement entrydata is received, and the book entirely consisting of the advertisementdata is produced. This book can be looked up by turning pagesconsecutively and it becomes possible to search the book while watchingthe advertisement entry.

[0280] Here, the format of the book data with the book code is notnecessarily limited to that shown in FIG. 44 and can be changedoptionally. Also, the format of the book data with the advertisemententry code is also not necessarily limited to that shown in FIG. 45 andcan be changed optionally. The manner for assigning the advertisemententry code and the book code is also optional. Also, the broadcastschedule table as shown in FIG. 46 which includes the items such as thebroadcast date, the broadcast station, the start time, the end time, thebook code, the book title, the publisher's name, and the author's nameis not absolutely necessary, and there is no limit to the number ofitems. The manner of entering the selection of the advertisement entryis also optional and can be the pointing using the mouse, or thekeyboard. The number of user terminals or the data centers are free asthey relates to the broadcast. The number of book data to be broadcastedis also optional. The form of the broadcasting is also optional, and canbe the wire broadcasting such as those using the optical fiber or thecoaxial cable, etc., or can be the radio broadcasting using the UHF,VHF, or the satellite.

[0281] As described, according to this fourth embodiment, by attachingthe advertisement entry of the other books related to a certain book, sothat the reservation of the book can be made in a state in which theadvertisement entry is displayed during the reading. Also, in a case ofstoring only the advertisement entry in the user terminal 430, the bookcan be searched while looking at the advertisement entry, and thedesired book to be stored can be reserved by specifying thecorresponding advertisement entry. As a result, it becomes possible forthe user to select and enter the book data which is absolutely neededfor the user. In other words, the storing operation of the broadcastedbook data can be carried out more smoothly, and as a result, theeasiness of the handling of the book data service system for displayingthe book data can be improved.

[0282] Next, the fifth embodiment of the book data service systemaccording to the present invention will be described in detail.

[0283] In this fifth embodiment, the book data service system has asystem configuration as shown in FIG. 49 where, the system configurationof FIG. 11 for the second embodiment described above is modified in thatthe computer 51D of the data center 50D has a reception and responseunit 491 which replaces the deciphering key returning unit 113 in FIG.11 and a data processing unit 492 which replaces the charging unit 114in FIG. 11. In addition, the user terminal 55B has a detailedconfiguration as shown in FIG. 50 where the configuration of FIG. 12 forthe second embodiment described is modified in that the computer 56D hasthe book data display unit 63D including a data editing unit 501 and areceipt notice display unit 502 instead of the book data inspection unit121 in FIG. 12, and a data transmission and reception unit 503 whichreplaces the deciphering key acquiring unit 122 and the deciphering unit123 in FIG. 12.

[0284] This fifth embodiment concerns with a scheme for communicatingthe data written into the book data by the user at the user terminal 55Dto the data center 50D.

[0285] It is to be noted that the above features of this fifthembodiment are totally unrelated with the characteristic features of thesecond, third and fourth embodiments concerning the deciphering functionand the charging function, and the communication devices 112A and 112Bcan be also used for the requesting and returning of the deciphering keyas well, so that it can easily be combined with the second embodiment.Also, by using the deciphering communication device 271 of the thirdembodiment for transmitting the data other than the book data withoutapplying any processing, this fifth embodiment can be combined with thethird embodiment as well. It is also obviously possible to combine thisfifth embodiment with the fourth embodiment concerning the storagereservation as well.

[0286] In this fifth embodiment, as shown in FIG. 53, it is assumed thatthe book data has spaces 531 for the user entry or the columns 530 forindicating choices. Also, when a plurality of data centers 50D areprovided, the communication network type (network ID) or the subscribernumber (subscriber ID) of the data center 50D to which the data are tobe transmitted should be given in the book data. Thus, in this fifthembodiment, the book data is given in a format shown in FIG. 52 whichincludes the book code 521, followed by a number of groups of the itemnumber 522, the data length 523, and the entered data 524, followed bythe communication network ID 525, the subscriber ID 526, and thesupplementary information 527 such as the title, author, publisher, etc.of the book, and finally the text data 528 of the book. Here, when thereis only one data center 50D for the user terminal 55D, there is no needto provide the communication network ID 525 and the subscriber ID 526 inthe book data. Also, the book data is to be displayed in a manner ofFIG. 1, but the transmission button 532 is added to the navigationbuttons as shown in FIG. 53.

[0287] Now, this fifth embodiment operates according to the datatransmission sequence between the user terminal 55D and the data center50D shown in FIG. 51 as follows. First, the book data management unit 62of the user terminal 55D is activated (a), and when the user selects thebook data on the book menu (b), the book data display unit 63D of theuser terminal 55D reads out and displays the selected book data (c).Next, in the book data display as shown in FIG. 53, when the user entersthe user entry into the user entry space 531 or specifies the choice inthe choice indication column 530 (d), the book data display unit 63D ofthe user terminal 55D enters the text data entered by the user or thesymbol or number selected by the user at appropriate positions in thebook data display as shown in FIG. 53. In the book data format of FIG.52, the item number 522 of the entered data 524 corresponds to theentered position on the book data display.

[0288] Next, when the user commands the transmission button 532 on thebook data display as shown in FIG. 53 (e), the user terminal 55Dactivates the data editing unit 501 which takes out the entered datafrom the book data and edits the transmission data (f). Here, in a casethe book data is in the format of FIG. 52, it suffices to take out thetop of the book data in a state having the data entry to the end of theentered data.

[0289] When the editing of the transmission data is completed, the datatransmission and reception unit 503 is activated (g), and the datatransmission and reception unit 503 activates the communication device112 to set up the communication path with the data center 50D (h), andtransmits the edited transmission data to the data center SOD (i). Here,when a plurality of data centers 50D are present from the viewpoint ofthe user terminal 55D, the network ID 525 and the subscriber ID 526 inthe book data in the format of FIG. 52 are utilized at a time of thecommunication path set up. When the entered data is received at thereception and response unit 491 through the communication device 112A inthe data center SOD (j), the data center 50D produces the receipt notice(k) and returns it to the user terminal 55D (l).

[0290] Then, the entered data are further processed at the dataprocessing unit 492, but the detail of this further processing is notessential to the present invention. Here, in a case the actual dataprocessing can also be made in a short time in addition to the receipt,instead of producing the receipt notice at the reception and responseunit 491, the data processing unit 492 produces the report of theprocessing result and returns it through the reception and response unit491, and then the data transmission and reception unit 503 of the userterminal 55D receives this report through the communication device 112.

[0291] When the returning of the receipt notice or the report iscompleted as it is received at the user terminal 55D side (m), thecommunication path is released (n) on both sides, and the receipt noticeis transmitted to the receipt notice display unit 502 from the datatransmission and reception unit 503 in the user terminal 55D, whiledeactivating the data transmission and reception unit 503 and thereceipt notice display unit 502 carries out the display of the receiptnotice (p). When the user confirms the displayed the receipt notice (q),the user terminal SSD resumes the usual book data display mode (r).

[0292] In this operation sequence of FIG. 51, when the amount of data issmall and the size of the entry frame is set up in advance at each page,it is possible to omit the data length 523 from the book data of FIG. 52by adopting the rule that the margins are to be sent in blanks. However,there may be a data center 50D which carries out the processingcorresponding to the book later on, so that it is preferable toincorporate the data length 523 in the book data.

[0293] Also, the editing of the transmission data is required in a casesuch as that which involves numerous entry spaces and not necessarilyall of them are filled, as in a case of marking the answers to theproblems and relatively grading the user's aptitude for instance. In acase involving only a few entry spaces, it suffices to send the entereddata as it is, with the unentered entry space as blank.

[0294] The received data at the data center 50D side is attached withthe book code or the item number in the prescribed format, so that it ispossible to judge which data content corresponds to which part of thebook, and the effective data can be extracted for use in the processingcorresponding to the book.

[0295] In this fifth embodiment, the entered data is given by thecharacter data indicating the choice or the key input, but it is alsopossible to enter the file name of the image file produced by thegraphics tool, and the file content can be transmitted in succession tothe file name transmission as an application of this fifth embodiment.

[0296] Also, the data transmission and the receipt notification aredescribed as being carried out in real time, but it is also possible toutilize the value added communication network having a long time storagefunction, in which case the communication network can receive the datatransmitted from the user terminal on behalf of the data center evenwhen all the data center side transmission lines are busy, and transmitthe received data to the data center when the data center sidetransmission line is released.

[0297] In this case, however, it is impossible to return the receiptnotice immediately, so that when the receipt notice from the data centeris received by the communication network, it is necessary for thecommunication network side to call up the user terminal and notify thereceipt notice, while on the user terminal side, it is regarded as notadmitted when there is no receipt notice within a prescribed period oftime. Else, the receipt notice waiting state can be monitored from thecommunication network, and the non-receipt notice can be notified fromthe communication network to the user terminal when the receipt noticefrom the data center is not received within a prescribed period of time.

[0298] As described, according to this fifth embodiment, the system forproviding the feedbacks from the user can be constructed such that theuser can enter the feedbacks such as the answers to the questionnaire inthe flow of the operation to read the book data, and can be relievedfrom the tediousness of using the mail or facsimile transmission of thefeedbacks. The effect of this system is not limited to making it easierfor the user to make the feedbacks, and the significant effect can beexpected in the development of the user participating type publicationculture.

[0299] Also, by utilizing this system in the ordering system using thecatalogue or the reservation system, as it suffices to provide only onedisplay program regardless of the content of the book data to bedisplayed, so that the user can be relieved of the tediousness toacquire and handle a number of programs suitable for a number ofdifferent order taking centers. In addition, the order taking side canbe relieved from the task of updating the user program even when theoffered items increase, and the communication requires as short time asthe dedicated system for order taking.

[0300] Also, in this fifth embodiment, it is possible to separate thedata display software in the computer into the book data display programand the book data, and the book data display program can be providedwith the function for allowing the user to enter the user entry into theuser entry spaces specified by the book data and the function forcommunicating with the data center, such that the data entered by theuser can be automatically transmitted to the data center by thetransmission command at the same level as the book data display command.Consequently, the user can enter the feedbacks without interrupting theflow of the book data reading operation, while the data center can enterthe received feedback data automatically into the host computer.

[0301] Also, the book data is produced according to prescribed rules,displayed according to prescribed rules and assigned with the book codeor the user entry space code, such that the same book data displayprogram can be used at the user terminal side regardless of the contentof the book data or the conditions of the data center side, and thecommunication with the data center can be established by simplytransmitting the entered data.

[0302] As illustrated by the above embodiments, according to the bookdata service system of the present invention, the book data aredistributed by the broadcasting so that the data in the book form whichis easy to handle and suitable for the comprehension of the large datacan be distributed at low cost, and the regional differences concerningthe availability of the books can be resolved. Here, when one channel ofthe television broadcasting is exclusively used for the broadcasting ofthe book data, the broadcasting time of the book data is of an order ofseveral seconds to several minutes except for cases involving thedynamic images, and the book data distribution cost can be expected tobe lower than the transportation cost required for the distribution ofthe conventional books as the number of subscribers increases to someextent.

[0303] Also, all kinds of book data are going to be available even atthe remote region which has no large bookstore or specialized bookstore,without any time difference. In addition, by providing the key fordeciphering the book data by the communication, or by renting thedeciphering device and making the remote inspection of the utilizationlevel record, it is possible to resolve the problem related to thecharging of the broadcasted book data.

[0304] Also, by providing the user entry spaces in the book data, it ispossible to provide the feedbacks to the data center almostautomatically without bothering the user to utilize the other media suchas mail or facsimile, so that the book data service system of thepresent invention can be utilized quite usefully in variety of purposessuch as the questionnaire, the order taking, the grading in an educationsystem using correspondences, etc.

[0305] It is to be noted that, besides those already mentioned above,many modifications and variations of the above embodiments may be madewithout departing from the novel and advantageous features of thepresent invention. Accordingly, all such modifications and variationsare intended to be included within the scope of the appended claims.

What is claimed is:
 1. A book data service system, comprising: at least one data center including: data center computer for storing and managing book data; and broadcasting means for broadcasting the book data stored and managed by the data center computer according to a prescribed communication protocol using a synchronization control and an error correction scheme suitable for data delivery by broadcasting without confirmation from a receiving side; and a plurality of user terminals, each user terminal including: receiver means for receiving the book data broadcasted from the broadcasting means of the data center; user terminal computer for storing and managing the book data received by the receiver means; and display means for displaying the book data stored and managed by the user terminal computer.
 2. The book data service system of claim 1, wherein the display means displays the book data in an image of a book.
 3. The book data service system of claim 1, wherein the user terminal computer manages the book data to enable retrieval and selection of the book data according to management information provided in the book data.
 4. The book data service system of claim 1, wherein the data center provides re-broadcasting of the book data, and the user terminal computer stores each book data which is incompletely received by the receiver means, and supplements said each book data by the book data re-broadcasted by the data center.
 5. The book data service system of claim 1, wherein the data center further includes data center side communication means for enabling one-to-one communication with each user terminal through a communication network, key returning means for returning a key for deciphering enciphered book data broadcasted by the broadcasting means through the data center side communication means to the user terminal which requested the key, and charging means for charging the user terminal which requested the key.
 6. The book data service system of claim 5, wherein each user terminal further includes user terminal side communication means for enabling one-to-one communication with the data center through a communication network, inspection means for inspecting whether the book data received by the receiver means is enciphered, key acquiring means for requesting the key to the data center through the user terminal side communication means when the inspection means finds the enciphered book data and obtaining the key returned from the key returning means through the user terminal side communication means, and means for deciphering the enciphered book data by using the key received by the key acquiring means.
 7. The book data service system of claim 5, wherein the enciphered book data is divided into a plurality of items, and the key for deciphering the enciphered book data is different for different item of the enciphered book data.
 8. The book data service system of claim 5, wherein the charging means charges a user using the user terminal every time the user terminal requests the key.
 9. The book data service system of claim 8, wherein the charging means charges a user using the user terminal in response to a request for the key from the user terminal after the enciphered book data is broadcasted by the broadcasting means and the key returning means returns the key to the user terminal after the user terminal is charged by the charging means.
 10. The book data service system of claim 8, wherein the charging means charges a user using the user terminal in response to a request for the key from the user terminal before the enciphered book data is broadcasted by the broadcasting means, and the key returning means returns the key to the user terminal after the user terminal is charged by the charging means and before the enciphered book data is broadcasted by the broadcasting means.
 11. The book data service system of claim 1, wherein the data center further includes data center side communication means for enabling one-to-one communication with each user terminal through a communication network, remote record inspection means for inspecting book data service utilization record at each user terminal through the data center side communication means, and charging means for charging said each user terminal according to the book data service utilization record inspected by the remote record inspection means.
 12. The book data service system of claim 11, wherein: each user terminal further includes user terminal side communication means for enabling one-to-one communication with the data center through a communication network, inspection means for inspecting whether the book data stored by the user terminal computer and selected by a user is enciphered, and deciphering request means for requesting a deciphering of enciphered book data to the user terminal side communication means when the inspection means finds the enciphered book data and obtaining deciphered book data from the user terminal side communication means; and the user terminal side communication means contains communicating means for making one-to-one communication with the data center through the communication network, deciphering means for deciphering the enciphered book data requested by the deciphering request means and returning the deciphered book data to the deciphering request means, recording means for recording the book data service utilization record whenever the deciphering means deciphers the enciphered book data, and means for returning the book data service utilization record recorded by the recording means through the communicating means to the remote record inspection means.
 13. The book data service system of claim 12, wherein the recording means records the book data service utilization record in terms of at least one of a time in use of the deciphering means, an amount of data deciphered by the deciphering means, and a number of cases deciphered by the deciphering means.
 14. The book data service system of claim 12, wherein the recording means records the book data service utilization record according to a book code of each book data deciphered by the deciphering means, so as not to change the book data service utilization record in a case of re-deciphering of once deciphered book data indicated by the book code.
 15. The book data service system of claim 1, wherein the book data broadcasted from the data center contains broadcast schedule table, and each user terminal further includes means for storing the broadcast schedule table, means for making a storing reservation of desired book data on the stored broadcast schedule table, means for inspecting whether the book data received by the receiver means is the desired book data for which the storing reservation has been made, where the user terminal computer stores only the desired book data for which the storing reservation has been made among all the book data received by the receiver means.
 16. The book data service system of claim 1, wherein each book data broadcasted from the data center contains an advertisement entry code assigned to an advertisement entry describing a content of said each book data briefly, and each user terminal further includes means for selecting the advertisement entry of a desired book data, means for memorizing the advertisement entry code of the selected advertisement entry, and means for comparing the advertisement entry code assigned to each book data received by the receiver means with the memorized advertisement entry code, where the user terminal computer stores only the desired book data whose advertisement entry code coincides with the memorized advertisement entry code.
 17. The book data service system of claim 1, wherein each book data broadcasted from the data center is assigned with a book code, and each user terminal further includes means for comparing the book code of each book data received by the receiver means with the book code of the book data already stored in the user terminal computer, where the user terminal computer stores only such a book data whose book code does not coincide with the book code of the already stored book data.
 18. The book data service system of claim 1, wherein: the book data broadcasted from the data center contains at least one of user entry spaces and choice indication columns; the data center further includes data center side communication means for enabling one-to-one communication with each user terminal through a communication network, and means for receiving user input data transmitted from the user terminal through the data center side communication means and returning a receipt notice through the data center side communication means to the user terminal from which the user input data is received; and each user terminal further includes user terminal side communication means for enabling one-to-one communication with the data center through a communication network, means for editing the user input data from data entered by a user in said at least one of user entry spaces and choice indication columns on the book data in response to a transmission command given by the user, means for transmitting the user input data to the data center through the user terminal side communication means and receiving the receipt notice returned from the data center through the user terminal side communication means, and means for displaying the receipt notice received from the data center for a confirmation by the user.
 19. The book data service system of claim 18, wherein the book data broadcasted from the data center contains a communication network ID and a subscriber ID used by the data center, and the user terminal side communication means sets up a communication path with the data center side communication means according to the communication network ID and the subscriber ID contained in the book data.
 20. A method for providing a book data service, comprising the steps of: storing and managing book data on a data center side by a data center computer of a data center; broadcasting the book data stored and managed by the data center computer according to a prescribed communication protocol using a synchronization control and an error correction scheme suitable for data delivery by broadcasting without confirmation from a receiving side; receiving the book data broadcasted from the data center at each user terminal; storing and managing the book data on a user terminal side by a user terminal computer of the user terminal; and displaying the book data stored and managed by the user terminal computer on a display in an image of a book. 